Vaccine
Successful
Smallpox Vaccination (22:V1:34-35)
The usual response
to a “first-time” or primary vaccination, or to a repeat
vaccination after a long period of time is called a “major” response.
This involves the development of a papule at the vaccination site
about 3-5 days following vaccination. Approximately 7 days following
primary vaccination, a vesicle (known as a “Jennerian vesicle”)
surrounded by erythema forms at the site. It then evolves into
a pustule by days 5-8. The peak site response occurs around days
8 to 10, and is when the greatest amount of erythema or swelling
is seen. Axillary lymph nodes may also be more swollen at this
time and the vaccinee may experience fever for a couple of days.
The site lesion then starts to dry up to form a scab at about day
14, with separation of the scab beginning about 14-21 days after
vaccination.

Vaccine sites
should be examined for the expected vesicle or pustule around day
7 following vaccination to confirm the vaccination was successful.
A revaccinated person often develops a skin reaction similar to
that after primary vaccination, but the lesion progresses faster
than after primary vaccination. (22:V6:58)
Some people
do not develop a typical skin lesion after vaccination. All responses
other than major reactions are referred to as equivocal. There
are several possible causes of equivocal reactions. (22:V6:61) The
person may be sufficiently immune to suppress viral replication.
Unless the person was recently vaccinated or vaccinated multiple
times in the past, they are probably not immune. The person may
be allergic to a component of the vaccine, which leads to a hypersensitivity
reaction at the site. An equivocal reaction could also be caused
by insufficiently potent vaccine or incorrect administration technique.
In general, a person who has an equivocal response to vaccination
should be revaccinated using vaccine from another vial, if possible. (22:V6:61)
A
revaccinated patient is considered to have had a major reaction
if they produce a pustular lesion or have an induration surrounding
a central crust or ulcer.
In general,
alcohol, soap and water, or other chemical agents are not needed
for preparation of the skin for vaccination unless the area is
grossly contaminated. If needed, soap and water are the preferred
cleaning agents. (22:V6:45) If any cleaning
agent is used, the skin must be thoroughly dry in order to prevent
inactivation of the vaccine.
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