This guideline describes the public health response to a case of smallpox. This guideline is intended to be used together with the national Plan for Smallpox Outbreak, Preparedness, Response and Management (Smallpox Plan) and jurisdictional smallpox response plans.
A single confirmed or probable case will initiate activation of the smallpox response plans. Other criteria for activation of smallpox response plans include:
Urgent. Respond to suspected, probable and confirmed cases immediately.
Smallpox has been eradicated as a naturally occurring infectious illness, with no known animal vector(1). The last naturally acquired case of smallpox occurred in 1977. The re-introduction of smallpox would constitute a Public Health Emergency of International Concern under the International Health Regulations (IHRs)(2). Any delays in reporting or responding to smallpox cases may severely impact disease containment(3).
Smallpox is a nationally notifiable disease, and a listed human disease under the national Biosecurity Act 2015(4, 5). Smallpox is a notifiable infection in NSW under the Public Health Act 2010
The aim is to isolate the infectious case and create a barrier of immune persons around the case (ring vaccination). Post exposure vaccination may prevent or modify disease. The following actions should be undertaken as soon as possible:
This surveillance and containment strategy may be supplemented with large-scale vaccination, based on risk assessments. Targeted mass vaccination in addition to the strategies listed above is important if there were a large number of index cases or delay in commencement of containment. Mass vaccination, of both affected and unaffected communities, may be undertaken.
Suspected, probable and confirmed cases should be immediately isolated and notified to the relevant Communicable Disease Branch (CDB) who will report to the National Incident Room (NIR). Immediately commence follow-up investigation. Early in an outbreak, laboratory confirmation should be sought in all cases. Subsequently, laboratory confirmation is not necessary in cases with clinical and epidemiological evidence. Undertake a clinical and exposure risk assessment in consultation with the Chief Human Biosecurity Officer (CHBO) and relevant infectious diseases service.
All contacts of a confirmed or probable case must be traced immediately. The following steps should be taken:
Smallpox is caused by infection with either of the closely related variola viruses: variola major and variola minor(1). Variola viruses are deoxyribonucleic acid (DNA) viruses of the genus Orthopoxvirus, which also includes vaccinia (used to produce the smallpox vaccine), monkeypox and cowpox.
Variola virus is thought to be unlikely to survive on its own for more than 24 hours when exposed to normal environmental conditions (ambient temperature, usual humidity and sunlight)(6, 7). The infectious dose is unknown (in aerosol it may be very low, e.g., only 10–100 virions) (1, 7, 8). Ten to twenty secondary cases may develop from each primary case(6).
Smallpox is a human disease with no known animal or environmental reservoir(1). There is no carrier state. Global eradication of smallpox was certified by the World Health Assembly in 1980.
Smallpox had household or close contact attack rates of up to 88%(9). Transmission occurred primarily via the respiratory tract (droplet spread) and to a lesser extent through direct contact such as from pustules. Close contact is usually required (i.e. within 2 metres)(1).
Less commonly, spread occurred from contaminated fomites such as bed linen or clothing(10). The duration of infectivity of fomites is unknown, but likely to be no more than a few days.(11) Spread through fine particle aerosols could occur if cough was present(1). Two hospital-based outbreaks resulting from airborne spread through air corridors have been described(12). The conjunctivae or the placenta were occasional portals of entry of infection(10).
Cases with more severe illness transmit smallpox more effectively than those with mild or moderate illness(12).
The incubation period for smallpox is 7–17 days; most commonly 12–14 days to onset of prodromal illness and 2–3 days more to onset of rash(7, 13).
Cases are not believed to be infectious prior to the onset of symptoms. Cases should be regarded as infectious from the onset of fever. Cases are most infectious from the onset of the rash and for the first 7–10 days of rash(7).
As a precaution and for the purposes of contact tracing, the infectious period is from 24 hours before recognition of fever or other prodromal symptoms until the last scabs from the rash fall off.
Cases have occurred after contact with corpses(14, 15). The duration of infectivity of corpses is unknown.
Typically smallpox infection has a 2–3 day prodromal stage which is characterised by an acute onset of high fever (≥38 °C) and constitutional symptoms such as malaise, prostration, headache, severe back pain and, on occasion, abdominal pain and vomiting(7, 16, 17). A maculopapular rash develops 2–3 days after symptom onset in which individual lesions containing infectious virus appear over a 1–2 day period and then progress over a period of 6 or more days through successive stages of macules, papules, vesicles, and pustules(1, 7). Vesicles are filled with clear fluid and often have a depression in the centre. The vesicles change to pustules which are round, well circumscribed, tense and firm (‘bullet like’) without an inflammatory flare(1). Crusted scabbing usually begins 8–9 days after rash onset. Scabs fall off leaving depigmented skin and, over time, frequently scars (pockmarks).
Classically the rash commences on the mucosa of the mouth and pharynx, then face, hands, forearms and feet (including palms and soles) before occurring on the torso (centrifugal distribution). The rash usually spreads to involve most of the body over a period of 24 hours. Lesions are usually more profuse on the face, forearms and lower legs than the upper arms, thighs or torso. Prominent surfaces and areas exposed to irritation are more heavily involved in the rash while protected surfaces are usually spared. Lesions are usually at the same stage of development in a given area of the body.
Variola major virus causes a severe illness with an overall fatality rate of 30% or more while variola minor virus causes a milder illness with a fatality rate of 1% or less(7).
The World Health Organization (WHO) classified smallpox into five phenotypes as follows(18):
Multiple complications may occur as a result of smallpox including bacterial infection, sepsis, arthritis, corneal ulceration with resulting blindness, osteomyelitis and encephalitis(1). In pregnant women spontaneous abortion and stillbirth may also occur.
In fatal cases, death usually occurred during the second week of illness(7). The exact cause of death in smallpox is unclear but is likely due to toxaemia resulting from circulating immune complexes and variola antigens(10). See Appendix C for a comparison of smallpox (variola) and chickenpox (varicella) infections.
The majority of the public will be susceptible to smallpox(1). Susceptibility is universal among those who have not had prior smallpox or been vaccinated. Routine vaccination of the Australian public ceased before 1980(23). The duration of immunity following immunisation is unknown, however it is thought that a single dose of vaccination will offer protection from infection for 5–10 years, and protection from fatal disease may be lifelong(1, 10, 24). Natural infection confers lifelong immunity(22).
Secondary cases are most likely in the household-like contacts or health-care contacts of cases as most cases self-isolate due to illness prior to the most infectious period(7). Classically, smallpox spreads in expanding rings of close contacts with waves of cases corresponding to the incubation period (normally 12–14 days)(25).
The last naturally acquired case occurred in October 1977 in Somalia(26). In 1978 two laboratory-related cases occurred in Birmingham, England(27). Global eradication was certified in 1979 by WHO, and sanctioned by the World Health Assembly in May 1980(10).
A case of smallpox could occur now through:
A small number of laboratory workers who work with smallpox-related viruses continue to be immunised.
Probable and confirmed cases should be entered onto the National Notifiable Diseases Surveillance System (NNDSS), ideally within one working day of notification. The date of onset is the date of onset of the illness, not of the rash.
Cases subsequently shown not to have smallpox should be removed from the NNDSS within one working day.
A single case of smallpox would result in activation of the Communicable Disease Incident of National Significance protocol. Media and communications should be coordinated in accordance with the Health CBRNINC Plan: Domestic Health Response Plan for Chemical, Biological, Radiological or Nuclear Incidents of National Consequence.
Clear roles and responsibilities and lines of communication are required to implement an effective response to a smallpox emergency. The state and territory health authorities are responsible for disease control. The role of Health will include overseeing the national response and supply of vaccine.
Health will nominate a Media Liaison Officer supported by the NIR who will work in conjunction with the AHPPC and the Attorney-General’s Department (AGD) Emergency Management Australia (EMA) to manage public information releases.
Health will provide overall national coordination, provide logistical support to states and territories and activate the NIR. Media releases will aim to reduce the potential for mixed messages and to ensure a common, national message to cases, their families and the general public. The common message will aim to ensure cases and their families receive consistent information about the responsibilities of all agencies involved and the nature of the response.
In the event that a national terrorist situation is declared, the media management arrangements that apply to such situations override the media management arrangements outlined above (refer to the National Counter-Terrorism Plan and National Counter-Terrorism Handbook).
Jurisdictional CDBs should notify suspected, probable and confirmed smallpox cases to the NIR by telephone (+61) 2 6289 3030 or email:
The case definition may have been updated since the publication of this guideline. Please check the
National surveillance case definitions webpage on the Australian Department of Health’s website for the latest version.
Both confirmed cases and probable cases should be notified.
A confirmed case requires laboratory definitive evidence only.
A probable case requires either:
Within 7 to 19 days prior to illness onset the case has:
A suspected case requires:
The Guidelines for Smallpox Outbreak, Preparedness, Response and Management include separate case definitions for smallpox surveillance both preceding and during an outbreak. The Guidelines define confirmed, probable, suspected and possible cases for the purposes of public health response. The definitions are at some variance with the case definitions for reporting to the National Notifiable Diseases Surveillance System.
Suspected cases and
possible cases should also be reported to the State/Territory health department.
1 In the absence of meeting the first criterion of the laboratory suggestive evidence, if confirmatory testing at a reference laboratory subsequently confirms the specimen as not being variola virus, this criterion would not be considered to have been met as the laboratory suggestive evidence component of the case definition.
2 Refer to the
Clinical presentation and outcome part of Section 2. The disease.
3 Such as an infectious diseases physician, clinical microbiologist or public health physician.
Initial testing for smallpox is undertaken at the National High Security Quarantine Laboratory (NHSQL) in VIDRL or the Institute of Clinical Pathology and Medical Research (ICPMR) (for NSW cases). Confirmatory testing is undertaken at VIDRL.
NHSQL should be notified through the relevant state or territory CHBO.
Polymerase Chain Reaction (PCR) is the primary diagnostic modality employed for detection of smallpox, and collection of appropriate vesicle swabs for this purpose is a priority. Rapid diagnosis is performed using variola-specific and orthopox real-time PCRs. Any positive result in either method must be confirmed using alternative PCR assays targeting different gene segments followed by sequence analysis to verify specificity.
Viral electron microscopy is available as an adjunct to PCR at VIDRL if required.
Smallpox is a Tier 1 Security Sensitive Biological Agent (SSBA) under the National Health Security Act 2007 (NHS Act) and requires storage in a Physical Containment (PC) Level 4 Laboratory.
The list of SSBAs defines which biological agents are of security concern. Tier 1 agents on the list of SSBAs are those agents that pose the highest level biosecurity risk to Australia.
When a patient with suspected smallpox is identified, the NHSQL at VIDRL will carry out testing of specimens. NHSQL should be notified through the relevant state or territory CHBO. However, direct contact with the medical microbiologist on call at VIDRL is essential to arrange receipt of specimens and obtain advice on specimen collection, safe packaging and transport. In the event of ongoing cases, VIDRL will advise on which PC3 or PC4 laboratories can receive specimens in the relevant jurisdiction.
Back up is provided by the following:
The recommended approach to smallpox testing will vary depending upon the current epidemiological context and threat level.
The threat categories used are:
Table 1: Laboratory test procedures for smallpox by response
3 More details regarding laboratory testing are available in Inger Damon, Hermann Meyer, & Shchelkunov, S. (2010). Laboratory diagnostics for smallpox (variola virus). In A. S. Khan & G. L. Smith (Eds.), Scientific review of variola virus research, 1999–2010. Geneva, Switzerland: World Health Organization.
PCR will almost always be the diagnostic modality used. Appropriate equipment includes:
If for particular reasons electron microscopy is required, the PCR requirements are supplemented by:
The procedure for collecting specimens of vesicle fluid is as follows:
The outside of each specimen container should be swabbed with disinfectant (5000 parts per million available chlorine) and a label should be attached bearing the patient’s name, hospital identification, date of collection and the nature of the suspected infection. The specimens should be double bagged in secure, airtight and watertight bags, which have been similarly labelled. Bags containing specimens should be sponged with disinfectant before being removed from the patient’s room.
Samples should be identified as infectious substances affecting humans (smallpox sample) and packaged and handled as required by International Air Transport Association (IATA) packing instruction 602.
The specimens should be packaged as follows:
National High Security Quarantine Laboratory
Victorian Infectious Diseases Reference Laboratory (VIDRL)The Doherty Institute792 Elizabeth StreetMelbourne VIC 3000
Use a competent door-to-door courier. As individual commercial and non-commercial carriers or shipping services may apply different regulations for transporting biological specimens, contact a representative of the chosen carrier beforehand to ensure that all necessary formalities are fulfilled.
Notify the on-call VIDRL medical microbiologist of the dispatch of the specimen and flight time and number, courier or air waybill number as appropriate. If transport is by air, a dangerous goods declaration must be made (refer to the IATA Dangerous Goods regulations).
Clinical samples from suspected cases must be handled with due regard to the likelihood that smallpox is present, and the appropriate procedures observed. Screening for the first case or cases will be centralised in the NHSQL’s PC4 facility. While smallpox remains eradicated or should community transmission of smallpox become re-established, smallpox exclusion and diagnosis may be performed by vaccinated staff in a PC4 laboratory. Should it be necessary to conduct work other than in PC4 laboratories, a full risk assessment must be conducted.
When specimens from suspected cases are sent to one of the designated PC3/4 regional laboratories for diagnosis, investigation will require:
Specimen collection and laboratory testing should be only be undertaken by appropriately trained personnel who are wearing appropriate PPE; ideally the personnel should have had a successful smallpox vaccination.
Staff at the designated PHLN jurisdictional laboratories will be vaccinated in the Standby Phase (for more information see the Smallpox Plan).
Wider vaccination of laboratory staff is not justified since the risks of adverse effects from vaccination outweigh the risk of developing smallpox. However, staff liable to be involved in diagnostic work should be identified and screened in advance for suitability for vaccination.
See Section 10. Contact management for information on risk stratification for laboratory personnel handling variola virus.
Suspected, probable or confirmed cases should be immediately notified to the central state or territory CDB who will need to notify the NIR urgently (via email
email@example.com or phone call 02 6289 3030). The NIR should report to the WHO as soon as possible.
A follow-up investigation should begin on the same day as notification for all probable and confirmed cases. The level of response to suspected cases will depend on the level of suspicion after discussion with the NIR and the state Chief Human Biosecurity Officer.
The aim is to identify the source of exposure (e.g. another case or environmental source) and primary contacts. The response to a notification will normally be carried out in collaboration with the clinicians managing the case. The PHU may need to work with local and national police.
PHU staff should ensure that action has been taken to:
Investigations will begin with a hypothesis-generating interview with every smallpox case (or caregiver) to pinpoint the case’s movements over the 17 days prior to the onset of the illness. If a hypothesis is formed for the source of infection, an analytical epidemiological study may be undertaken in parallel with a police investigation.
Interviews with suspected, probable or confirmed cases should be undertaken by telephone where possible, but if undertaken face-to-face, the person conducting the interview must be known to be immune to smallpox or have a thorough understanding of the indicated infection control practices and be competent in using appropriate personal protective equipment (PPE) (see Section 12. Infection control). Treating staff may conduct the interview rather than public health staff to reduce the number of people with contact to the case.
Treatment of a case is the responsibility of the clinician in consultation with an expert virologist. Use of antivirals may be indicated such as cidofovir, or antivirals which have not been tested against variola but have activity against pox viruses such as brincidofovir (CMX001), tecovirimat (ST-246), ribavirin and rifampicin(1).
Provide the case with Appendix A: Smallpox factsheet.
Suspected, probable and confirmed cases, and any person who requires assessment to determine if they are a suspected case, should be immediately isolated and transferred to hospital using appropriate infection control procedures. If hospital facilities are at capacity, suspected smallpox patients who do not require hospital care may be isolated in non-hospital facilities that do not have shared ventilation systems with other facilities. Cases should remain isolated until all scabs have separated or smallpox is excluded.
For further detail, including related to deceased persons, see Section 12. Infection control.
Alert local doctors and laboratories in the areas where the smallpox case may have acquired infection or was infectious and
Identify primary contacts and categorise by their risk of developing infection.
Note: persons with a confirmed history of smallpox are not at risk.
Higher risk primary contacts of a suspected, probable and confirmed smallpox case include:
Lower risk primary contacts of a suspected, probable and confirmed smallpox case include:
Note: Transient or distant contacts should not be managed as lower risk primary contacts.
4 Contacts are classified as unvaccinated if they have not been successfully vaccinated against smallpox within the past 3 years. A successful vaccination requires a confirmed ‘take’ or major reaction indicating immunity.
5 Contacts who would otherwise be lower risk primary contacts but who are unable to be vaccinated and are now classified as a higher risk primary contact do not need to be managed as a higher primary risk contact regarding vaccination.
Contact management of laboratory personnel depends on a risk assessment of the type of exposure and work context. Vaccination will occur when a trigger event happens and the NHSQL is alerted by the NIR.
Four levels of hazard are identified for medical testing laboratory personnel:
Table 2: Laboratory personnel hazard levels and contact risk assessment
Identify household-like contacts of higher risk primary contacts.
Contacts of higher risk primary contacts of a suspected, probable and confirmed smallpox case include:
Contacts require vaccination, monitoring and movement restriction as detailed in the sections below.
Vaccination should be carried out as soon as possible, preferably within 3–4 days and at most within 7 days following exposure to a confirmed case(1, 29). The degree of protection from vaccination diminishes as the interval between exposure and vaccination increases.
Primary contacts should be checked for symptoms before vaccination, to ensure that they are not co-primary cases.
For details on vaccination contraindications see Section 11. Smallpox vaccination.
Should be vaccinated unless they have a relative or absolute contraindication, in which case the risk from vaccination should be weighed against the risk from disease.
The vaccination site should be reviewed by an immunised, trained clinician after three days to assess for a successful vaccination. Contacts who fail to show a response to a first dose of vaccine after three days should be re-vaccinated. Lower risk primary contacts who fail to demonstrate a successful vaccination after the second attempt or who are unable to be vaccinated are re-classified as higher risk primary contacts.
All primary contacts should be monitored. Formal monitoring with daily contact for development of smallpox is recommended for higher risk primary contacts and desirable for lower risk primary contacts (use Appendix E: Contact surveillance form).
Public health emergency powers may be invoked to restrict activities of primary contacts. The restriction period is the time during which primary contacts are at risk of developing symptoms and becoming infectious. The restriction period extends from the first exposure until 17 days after the last exposure to an infectious case. It is unlikely that the contact will be infectious during the first 7 days after exposure. Material and social support should be provided.
Primary contacts during the restriction period must:
Secondary contacts (household-like contacts of higher risk primary contacts):
Vaccine non-responders, primary contacts who receive late vaccination (more than 4 days after their first exposure to infection), and primary contacts who refuse vaccine or are unable to be vaccinated may be given additional prophylaxis against smallpox in an effort to attenuate disease. This may be given concurrently with (re)vaccination.
Supplies of additional prophylaxis should be prioritised to those most at risk of disease:
All contacts should be counselled about their risk and the symptoms of smallpox and provided with Appendix A: Smallpox factsheet, Appendix F: Advice for contacts of a case of smallpox and Appendix G: Vaccination factsheet.
6 Any contact who has been reclassified as higher risk primary contact as he/she could not be vaccinated, still should not be vaccinated.
The smallpox vaccine is currently the only way to prevent smallpox, although there has been work on antivirals, such as tecovirimat, to treat the disease. The vaccine is made from a vaccinia virus, another pox-type virus related to smallpox, which cannot cause smallpox. The vaccine helps the body develop immunity to smallpox and was successfully used to eradicate smallpox from the human population.
In the absence of any clear evidence that smallpox may re-emerge or that it is used in an act of biowarfare or bioterrorism, the risk of adverse events from the vaccine outweighs the risk from the disease(30).
Vaccination within 3 days of exposure with replication-competent smallpox vaccine (Aventis Pasteur Smallpox Vaccine(APSV), ACAM2000 or LC16m8 vaccines) will prevent or significantly lessen the severity of smallpox symptoms in the vast majority of people(1, 31). Vaccination 4 to 7 days after exposure likely offers some protection from disease or may modify the severity of the disease(29).
Traditional smallpox vaccines are based on replicating vaccinia virus strains. Although these vaccines have been effective in eradicating the disease, their use has been associated with a significant risk of adverse events, including severe disability and death. Smallpox vaccines produced and successfully used during the eradication program are called first generation vaccines. Second generation smallpox vaccines use the same smallpox vaccine strains employed for manufacture of first generation vaccines or clonal virus variants plaque purified from traditional vaccine stocks, whereas third generation smallpox vaccines represent more attenuated vaccine strains specifically developed as safer vaccines at the end of the eradication phase by further passage in cell culture or animals.
In the event of an outbreak, the containment strategy will centre on the isolation of cases and vaccination of contacts. In a public health emergency involving smallpox, vaccination with replication-competent smallpox vaccine (i.e. ACAM2000 and APSV) will be the primary response strategy for stopping the chain of transmission and achieving epidemic control. Persons at high risk for complications from replication-competent smallpox vaccines are often at higher risk for severe smallpox. Consequently, persons with a known exposure to smallpox virus (higher risk contacts) should be vaccinated with a replication-competent smallpox vaccine unless absolute contraindications, and lower risk contacts should be vaccinated with a replication-competent smallpox vaccine unless absolute contraindications or relative contraindications(31).
Table 4: Absolute and relative contraindications to use of replication-competent smallpox vaccine
Smallpox vaccination will be undertaken by HCWs trained in administration of smallpox vaccine. The smallpox vaccine is given using a bifurcated (two pronged) needle that is dipped into the vaccine solution. When removed, the needle retains a droplet of vaccine solution. The needle is used to prick the skin a number of times in a few seconds. The pricking is not deep, but it will cause a sore spot and one or two droplets of blood to form. The vaccine is usually given in the upper arm.
A successful vaccination requires a confirmed ‘take’ or major reaction indicating immunity. If the vaccination is successful, a red and itchy bump develops at the vaccine site in three or four days. In the first week, the bump becomes a large blister, fills with pus, and begins to drain. During the second week, the blister begins to dry up and a scab forms. The scab falls off in the third week. People who are being vaccinated for the first time have a stronger reaction than those who are being revaccinated.
As specified in Section 10. Contact management, if a higher risk primary contact has severe skin disease or immunosuppression, they may be given VIG to prevent vaccine complications, depending on supplies(1). Adverse events following immunisation may be treated with cidofovir, although renal toxicity may limit its use.
In addition to cases and contacts, an emergency vaccination program would include HCWs at clinics or hospitals that may receive patients; essential emergency response personnel, such as police, ambulance, fire, and emergency services; laundry staff, public health and emergency management staff; and mortuary staff who may handle bodies. Such staff would need to be vaccinated even if they have been immunised previously. Vaccination would be prioritised for staff likely to have direct contact with the patient, or their clinical specimens or fomites.
After vaccination, it is important to follow care instructions for the site of the vaccine. Provide all vaccinated persons with Appendix G: Vaccination factsheet. As the vaccine contains live virus, it can potentially spread to other parts of the body, or to other people.
Imvamune is a new smallpox vaccine based on MVA-BN® (a strain of the Modified Vaccinia Ankara virus). It is injected like other modern vaccines rather than pricked into the skin with a bifurcated needle. While the MVA-BN virus is highly attenuated and is thus incapable of replicating in the body, it is still capable of eliciting a potent immune response and does so without producing the post-vaccination complications associated with traditional smallpox vaccines. The strain of vaccinia virus contained in Imvamune was not used during the eradication of smallpox and its efficacy in preventing smallpox in humans in an outbreak is less certain. Furthermore, Imvamune requires 2 doses administered 4 weeks apart to achieve an immune response comparable to that of replication-competent smallpox vaccines. Although persons vaccinated with Imvamune might have a lower risk for serious adverse events, this might be outweighed by the uncertainty in clinical effectiveness to prevent disease and provide rapid protection.
The National Medical Stockpile (NMS) is the main source of smallpox vaccine in Australia. The Secretary of the Australian Government Department of Health and the Commonwealth Chief Medical Officer (CMO) have authority to approve an NMS deployment on request from state or territory authorities.
These infection control procedures must be observed by all persons who are involved in the care of or in contact with suspected, probable and confirmed cases of smallpox, including visitors to patients, ambulance personal and healthcare staff. All staff caring for a smallpox patient must be (recently or immediately) vaccinated against smallpox. Staff for whom vaccination is contraindicated should not come into contact with any patient with suspected, probable or confirmed smallpox or their (including recently vaccinated) contacts. Anyone having close contact with a smallpox patient must wear PPE.
A risk assessment approach should be performed to assess the correct level of PPE for providing care to a suspected, probable or confirmed smallpox patient. A risk assessment should take into account the patient’s history of exposure to smallpox, their symptoms, the risk of transmission and the type of healthcare activity that will take place.
During acute disease, the main hazards are:
Strict hand hygiene with alcohol-based hand rub (ABHR) or disinfectant (liquid) soap should be carried out immediately before and after all episodes of care, including before putting on and after removal of gloves.
A risk assessment approach should be used before every interaction with a symptomatic patient with suspected, probable or confirmed smallpox, to determine the need for additional infection prevention and control measures, such as enhanced PPE.
PPE must be used by HCWs (including vaccinated personnel) caring for any patients with suspected, probable or confirmed smallpox. At a minimum, PPE should include a fluid-resistant gown and protection of the hands and mucous membranes of the eyes, mouth and nose. All skin and hair should be fully protected if aerosol-generating procedures are being performed or likely to be required urgently.
PPE should be adequate but not excessive. Wearing PPE in excess of that recommended, will potentially restrict movement and vision, increase the risk of heat stress, and make putting on and taking off PPE more complex. The risks, to the HCW or patient, of using items in addition to those recommended may outweigh any theoretical benefits.
Putting on and taking off PPE must be done slowly and methodically, according to an agreed sequence, and supervised by a trained buddy.
Staff and visitors should change when leaving the infected area. They should remove isolation facility clothing and shower before donning their street clothing and shoes. Hair washing should not be necessary if a hair cover is used.
Isolation of suspected, probable or confirmed smallpox patients may be accomplished by several different methods, depending upon various factors (number of patients, severity of illness, availability of resources etc.). The ultimate goal of isolation is to prevent transmission of smallpox from a patient who is infectious (from onset of symptoms until all scabs have separated) to non-immune individuals, whilst maintaining an appropriate care and comfort level for the patient and their carers. All potential methods of patient isolation must be considered with these goals in mind. Several are outlined below, but healthcare personnel should consult with infection control experts and/or public health officials to determine the most appropriate isolation method.
All suspected, probable and confirmed smallpox patients as well as any person who requires assessment to determine if they are a suspected case, should be isolated in hospital as follows:
Public health officials should be consulted before non-hospital isolation is initiated. In special circumstances, such as when hospital capacity is reached, suspected smallpox patients who do not require hospital care may be isolated in non-hospital facilities that do not have shared ventilation systems with other facilities, so long as appropriate compliance can be assured and support provided by recently vaccinated carer(s) (relative, friend, community health worker).
Non-hospital isolation facilities should have appropriate climate control capabilities (heating, air-conditioning), running water and bathroom facilities. All persons entering these facilities must have documented successful, recent smallpox vaccinations.
A suspected case may be released from isolation and discharged, if the medical condition allows, after testing negative for smallpox.
Probable and confirmed cases may be released from isolation in consultation with an infectious diseases physician and public health authorities.
Staff responsible for environmental cleaning and/or disposal of waste generated during the care of patients with infectious diseases of high consequences, including smallpox, should be informed of potential risks but reassured that risk can be minimised with the careful use of recommended procedures and appropriate PPE. They should be trained (and regularly retrained) in and confident with correct procedures for donning and doffing of appropriate PPE to minimise the risk of accidental contamination and/or industrial action and refusal to undertake these activities. A record should be kept of staff involved in packaging, handling and transport of waste material or linen.
Diligent environmental cleaning, disinfection and safe handling of potentially contaminated materials are required as infected body secretions represent potentially infectious materials. Environmental cleaning should be undertaken using either a two–step cleaning with detergent followed by disinfectant, or a combined 2-in-1 cleaning with detergent and disinfectant. Only disinfectants that are effective and approved by the Therapeutic Goods Administration should be used, and they must be used at the recommended strength following the manufacturer’s instructions.
The following section is modified from “Infection prevention and control principles and recommendations for Ebola virus disease”(34):
These recommendations are based on the following assumptions:
For the purposes of packaging and transport by rail or road, all such clinical waste should treated as a Category A infectious substance under the Australian Dangerous Goods Code until it can be sterilised or decontaminated (e.g. in an autoclave, by incineration, high temperature laundering or chemical disinfection).
The equipment in the patient room must be limited to what is essential for patient care. All equipment must be dedicated for that patient’s sole use and remain within the room for the duration of their hospitalisation. Single-use equipment should be used whenever possible. Large, reusable pieces of equipment, such as mattresses and critical medical equipment are safe for reuse if their surfaces can be properly cleaned and decontaminated. If not they should be discarded.
Clinical waste may also be generated in the home, community or ambulatory healthcare settings, where a person with smallpox has been cared for before admission to a hospital isolation unit. Any items potentially contaminated with smallpox virus should be treated as Category A infectious waste.
Smallpox outbreaks have occurred among laundry staff handling smallpox contaminated clothes or bedding. Only vaccinated personnel should handle laundry (bedding and clothing) or clinical waste potentially contaminated with variola virus. Standard practices to safely contain contaminated laundry and prevent direct contact or generation of aerosols should be followed. Laundry should be placed, with minimal agitation, directly into biohazard bags, without sorting and securely contained in a rigid lockable bin for:
Data on viability of variola virus in the environment is largely based on that of vaccinia and other pox viruses. It is highly resistant to drying, especially when shed in dermal crusts, blood or secretions, over a wide range of temperature, but is killed by moist heat. Nevertheless it can remain viable, if released as an aerosol for several hours, even at relatively high humidity and temperatures. Therefore, contaminated surfaces can be a source of transmission. Due to its low lipid content, it is less sensitive to organic solvents/disinfectants than other enveloped viruses. However, it is sensitive to all common approved disinfection regimens(35).
Surfaces that may be contaminated with variola virus can be decontaminated with disinfectants that are used for standard hospital environmental disinfection, such as freshly reconstituted sodium hypochlorite (500–1000 ppm (0.05–0.1%), after thorough cleaning (removal of all organic material) with detergent or with a combined detergent/disinfectant agent.
Heat is the most effective antimicrobial agent and viable counts of the smallpox virus are reduced within an hour or less by exposure to 60 °C.
Whenever possible, contaminated articles should be destroyed by incineration. If this cannot be done, articles should be sterilised in an autoclave where practicable. If neither incineration nor sterilisation is practical, chemical disinfection should be considered using 0.1% hypochlorite, vaporised hydrogen peroxide or ethylene oxide in a special chamber.
Disposable and clinical waste should be double-bagged and placed in rigid, lockable bins on wheels for transport by a specialist waste disposal contractor for incineration. As the action of loading and unloading can expel air and fluid, bags should preferably be closed by heat-sealing.
The decontamination process for premises differs according to the patient’s stage of illness. Virus from respiratory secretions is less protected by organic matter and is easier to disinfect than virus from crusts dried on the skin and bedclothes.
Any reusable equipment should be decontaminated before it is removed from the isolation room or reused. Any visible contamination should first be removed using a hospital-grade disinfectant wipe (e.g. chlorine disinfectant).
The item should be cleaned and disinfected using a two-stage process: a neutral detergent followed by a sodium hypochlorite solution (0.05-0.1%)(34). Vaporised hydrogen peroxide (if available) is also suitable for terminal cleaning of equipment or the patient room after cleaning with neutral detergent. The manufacturers’ instructions should be followed.
If the patient has developed a pustular rash while in the premises, the rooms should be cleaned with a vacuum cleaner incorporating a disposable liner inside its cloth bag. The cloth bag should be sterilised after use, but the liner and its contents must be burned. The vacuum cleaner should be sterilised after its use. The vacuum cleaner should be one designated for hospital use (one that is equipped with a HEPA filter at the air exit point). The vacuum cleaner should be thoroughly wiped down after use with freshly prepared sodium hypochlorite 0.05-0.1% (500–1000 ppm).
Ambulances that have carried patients with suspected, probable or confirmed smallpox, and their contents should be disinfected by ambulance crews. Clinical waste, laundry and stretcher canvases should be double bagged and disposed of as described above. The crew must not discard their protective clothing until disinfection of the vehicle has been completed.
All removable fittings inside the vehicle, including any loose floor coverings, should be removed, washed in detergent and hot water or wiped with detergent to remove visible dirt and disinfected with freshly prepared sodium hypochlorite solution 0.05-0.1% (500–1000 ppm) and wiped dry. The interior of the vehicle, including the driver’s cabin (particularly the steering wheel, brake and gear levers and other controls), should be cleaned with detergent, wiped or sprayed systematically with sodium hypochlorite: first the floor; then the roof; and last the sides, front and rear, including the inside of the door. The handle on the outside of the door should also be disinfected. Alternatively a small portable vaporised hydrogen peroxide system can be used to disinfect the interior of the vehicle.
After disinfecting the ambulance, the crew should:
Smallpox has occurred from transmission of variola from deceased smallpox cases(14) (See Section Infectious period). The body and immediate environment of the deceased are likely to be contaminated with variola and therefore scrupulous attention to appropriate PPE and cleaning procedures is required.
Bodies of smallpox cases should be safely and promptly disposed of. Only vaccinated personnel trained in handling infected human remains and wearing appropriate PPE should touch or move the body of a person with smallpox.
Cremation is the preferred option, and the advantage of cremation over burial should be explained to relatives as soon as possible(7). Disposable coffins, which are consumed by the cremation process, should be used.
Before removal from the deathbed, the body should be placed in a large, impervious plastic bag, or a disaster pouch, that is sealed airtight with tape and then sealed in a second large, impervious plastic bag prior to being placed in the coffin (preferably in the isolation room, where the patient died).
The coffin should be sealed with the lid secured, and the outside of the coffin washed down with freshly prepared sodium hypochlorite 0.05-0.1% (500–1000 ppm).
Autopsy should be avoided unless directed by the coroner because infections have been transmitted in this setting. If possible the examination should be limited to the organs/tissue necessary to establish the diagnosis or cause of death (if this is in doubt).
To transport the body to the mortuary, the body should be contained in line with disposal of the body.
Morticians, mortuary workers or medical laboratory scientists, who will handle bodies infected with smallpox, should be recently vaccinated.
Extreme care should be taken to prevent dissemination of variola virus. Contact and airborne precautions should be observed for all contact with the body. Vaccinated personnel should wear disposable clothing, gowns, gloves, caps, booties, masks and face shields or protective eyewear to prevent splashing of the mucus membranes. No personal clothing should be worn. If vaccination prior to participation in the burial preparation is not possible, unvaccinated personnel should wear additional respiratory protection (e.g., PAPR or equivalent).
All clothing articles from the preparation room should be placed in biohazard bags and sterilised in an autoclave or incinerated. Surfaces that may be contaminated with variola virus can be decontaminated with disinfectants that are used for standard infection control, such as hypochlorite or quaternary ammonia. After post-mortem examination the body should be double bagged in another set of impervious plastic bags before being placed in a disposable coffin for cremation.
Autopsy should be performed in a room with HEPA-filtered negative air pressure with respect to surrounding facilities. All doors and windows of the autopsy rooms should be closed during the preparation.
All staff members who have come into contact with the body should be managed as for HCWs caring for living patients with smallpox.
For research purposes, variola virus is retained in two secure facilities in Russia and the United States of America. Unauthorised access to the virus is extremely unlikely. If it were released, variola virus is considered one of the most dangerous viruses in existence. With a population that is largely non-immune, highly mobile and living in densely populated urban areas, a release or intentional infection of one or more persons could conceivably lead to a national epidemic or even a global pandemic.
The most likely smallpox threat to Australia is via air travel from an overseas incident. The expected outcome of this form of release would most likely be large numbers of cases with clustered onsets. Establishing epidemiologic association amongst these cases could be problematic, depending on the site and extent of virus dispersion. If introduced through intentionally infected persons, the origin of the virus (index case) and the extent of the outbreak could likely be tracked using standard epidemiologic and laboratory methods.
Proper selection of PPE for emergency first responders must be based on the hazards anticipated to be present at the scene and the probable impact based on the responder’s role. At a minimum PPE should include a fluid resistant gown, protection of the hands and protection of the mucous membranes of the eyes, mouth and nose.
There is negligible public health evidence regarding management of smallpox cases occurring on aeroplanes. Management of any infectious cases occurring on an aeroplane would be assessed on a case by case basis.
[Smallpox is a scheduled medical condition and notifiable disease under the
NSW Public Health Act 2010 with notification required by medical practitioners, hospitals and diagnostic laboratories.]
The contact details for the NSW Health Communicable Diseases Branch are (CDONCALL): Phone - (02) 9391 9195