These infection control procedures must be observed by all healthcare and emergency staff who are involved in the care of suspected, possible, probable and confirmed case of smallpox, including members of smallpox teams, ambulance personnel and healthcare staff working at smallpox care centres. They must also be observed by visitors to smallpox patients.
From the onset of fever, respiratory secretions are infectious and airborne transmission is possible. Body fluids are also highly infectious. Infectiousness increases for the next 4 to 7 days until the onset of vesicular rash and remains high for the next 7 days. Thereafter infectiousness wanes, but the pustules of the rash, and the dried scabs, which remain embedded in the skin during early healing, both contain infectious virus.
Patients with the most severe forms of the disease remain infectious for the three to ten days of their survival. Others may be diminishingly infectious for up to three weeks or more, until their acute disease is over, convalescence is established and all scabs are finally shed.
During acute disease the main hazards are:
Healthcare staff will be immunised before contact with smallpox patients. They will therefore be very effectively protected against significant clinical disease. However, a small proportion may develop very mild feverish illness, and may be infectious for a transient period of time. They should therefore be educated about this, and be aware that they should avoid contact with others during their period of fever.
In the past, smallpox nurses were isolated in the smallpox hospital while caring for their patients. This may not be acceptable nowadays, but it may be necessary to make provision for the comfortable isolation of healthcare staff with fevers.
Healthcare staff may become contaminated by body fluids, droplets or scabs, which could be deposited on carers clothing or hair. They should therefore change into appropriate clothing before entering the infected area for their work period.
Appropriate clothing would be theatre cottons with head covers, disposable aprons, eye protection and high efficiency face masks such as the 3M 8835 facelet. (This is a filtering face mask made for a 8 hour working day. It has a protection factor of around 100, protects against 0.2-10 micron particles, and is thought to be adequate for low challenge levels.) Footwear that is only worn within the facility is preferable to overshoes.
Strict handwashing with a disinfectant soap should be observed immediately after all episodes of care even if sterile gloves have been worn. On leaving the infected area, staff should change their outer clothing. They should then shower and wash their hair before donning their usual street clothing and leaving the clinical facility.
Household contacts of healthcare and ancillary staff should be vaccinated to minimise the possibility of accidental transfer of infection by close contact immediately after duty periods, or by close contact during a carer's mild feverish illness - see Section VIII. Whilst caring for smallpox patients, these staff should avoid close contact with people who cannot be vaccinated due to contraindications.
Decontamination of non-disposable linens and clothing should be possible by hot-cycle washing. Used items should be packed, without shaking, into laundry bags containing an inner bag with alginate stitching. This bag can be gently released from the outer bag and should be gently placed into a hot wash at least 71
oC. Because a number of outbreaks have occurred in laundry workers who handled linen and blankets used by patients, in an outbreak setting all such staff, and in addition their household contacts, should be vaccinated. If laundry has to be processed by non-vaccinated staff, then it must be autoclaved first. The outer bag should also be gently placed into the hot wash. Solid objects should be decontaminated by thorough cleaning with 0.1% hypochlorite.
Disposables and clinical waste should be placed in clinical waste bags. As the action of loading and unloading can expel air and fluid from bags that have been closed simply with ties, clinical waste bags should preferably be closed by heat-sealing. They should be disposed of by incineration without delay. No articles should be removed from the care centre without express permission from the person in charge and without appropriate laundering or disinfection.
In the days when many families sent out their linens to laundries, laundry workers who handled and sorted unwashed linens and clothing were at high risk of infection with smallpox. In the modern world of limited incineration of waste, and much recycling, it is common practice for household waste to be sorted by hand before incineration. By this means, glass, cans, batteries and other items are removed for separate processing. This procedure may place refuse workers at risk of contact with discarded disposable wipes, dressings and soiled linens from households where a case of smallpox has occurred.
Care must be taken that all items leaving an area where smallpox cases are cared for should be adequately decontaminated, or securely packed and handled as infected waste. All workers involved in handling such items and in addition their household contacts, should be vaccinated.
After wards, rooms or other areas have been vacated by smallpox patients, then these areas must be decontaminated. - see
Appendix 15.