Isolation & Quarantine Measures in Response to a Smallpox Emergency

Isolation Strategies

In a smallpox outbreak, there are 3 groups to consider when formulating isolation strategies. The first group is confirmed or suspected cases that would be considered immediately infectious to others. Vaccinating contacts to smallpox cases that become febrile and may be developing smallpox or may be febrile from the vaccination or some other reason (potentially infectious). The third group is vaccinated contacts to smallpox case that don’t have any symptoms but who are still in the surveillance period for the development of smallpox (not currently infectious but could still develop smallpox)

Smallpox cases require precautions that were previously discussed to prevent available, could be isolated individually in hospital isolation rooms. Patients could also be isolated with other suspected cases in a separate facility that is designed for their use only and does not have a shared ventilation system with any other facility. All persons (including patients) within facility would have to be protected by vaccination. Vaccination will:

  1. Prevent patients that are mistaken for smallpox patients (varicella) from becoming infected when they are exposed to true smallpox patients.
  2. Prevent others that enter facility from becoming infected following exposure via shared airspace.

Also, there must be the capability of providing some medical care if non-medical facility used for group isolation.

If groups of suspected patients are isolated in a facility designated only for care of smallpox patients, then:

  1. There is NO need to have special isolation rooms
  2. Make sure that ventilation system (including heating and air conditioning systems) are shared with any other facility.
  3. All persons entering facility must have been successfully vaccinated recently (including patients admitted to facility).

Strategies for Isolation of Febrile Contacts

Recently vaccinated contacts who have a fever but do not have a rash, may or may not be manifesting the first signs of smallpox. They need to be watched carefully to see if the fever is from the prodrome of smallpox or if it is from the recent vaccination, could be infectious if developing early symptoms of smallpox.

These people can also be isolated in hospital negative pressure rooms if available while observing for development of rash, or they can isolated in a different facility with other febrile contacts or cases. The same facility requirements exist for febrile contacts as for confirmed cases. An additional option is to keep person isolated at home and moving to smallpox isolation facility only if develops rash. If home isolation is followed, then ALL people entering or living in home must be vaccinated.

Strategies for Isolation of Asymptomatic Contacts

Recently vaccinated contacts to smallpox cases that do not have any symptoms are not infectious so don’t require facilities with any special ventilation. They can be monitored in their home for development of a fever (check at least twice a day). They can be asked to stay at home during surveillance period for symptoms or may be allowed to travel outside of home if distance is restricted such that a quick return to home is possible if develops fever. All others staying in home must be vaccinated in case the contact develops smallpox. Other household members with vaccination contraindications that can’t be vaccinated to protect themselves if the contact does develop smallpox while at home under surveillance should stay elsewhere until the contact is no longer at risk of developing the disease. 

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