Chapter 6 Part A: Post-event.
Screening individuals
for vaccination during a smallpox emergency,
with Dr. Brett Petersen.
In Chapter 6 of this training video,
we will discuss post-event vaccination
and screening individuals
for vaccination during a smallpox emergency.
Relative contraindications
and special populations will also be discussed.
In a post-event setting, the primary response strategies
to control and prevent the spread
of smallpox will include a vaccination program along
with surveillance and containment activities.
Because replication-competent smallpox vaccines have been used
successfully in past eradication campaigns,
these vaccines will be preferentially utilized
in the response strategy.
The replication-deficient vaccine, Imvamune,
may be made available for use in individuals
with certain medical conditions and/or
with relative contraindications depending on their risk
for smallpox infection.
Thus, healthcare providers
and vaccine administrators should be aware
of the available smallpox vaccines,
usage of these vaccines,
screening for relative contraindications
to smallpox vaccination, and anticipatory guidance
for vaccinees and/or individuals that cannot receive vaccination.
Recommendations for the use
of ACAM2000 during a smallpox emergency are based upon an
individual's risk for smallpox infection,
risk for an adverse event following vaccination,
and benefit from vaccination.
No absolute contraindications exist for smallpox vaccination
in a post-event setting.
However, there are several medical conditions
that will be described in more depth under
"relative contraindications" that have a substantial impact
on the risk-benefit analysis and should be incorporated
into the vaccination decision-making process
when screening individuals for ACAM2000 vaccination.
Individuals can be categorized into those exposed
to the smallpox virus and those who are at high risk
for smallpox infection but without a known exposure
at the time of vaccination.
Individuals exposed to smallpox, including those
with relative contraindications, should be vaccinated
with ACAM2000 unless they are severely immunodeficient.
However, individuals at high risk for smallpox infection
without a known exposure
to smallpox virus should be screened
for relative contraindications to smallpox vaccination prior
to administration of vaccine.
Individuals exposed to smallpox are defined as:
Individuals directly exposed to an accidental
or intentional smallpox virus release Household family members
of persons with confirmed, probable, or suspected cases
and others spending greater than or equal to 3 hours
in the household since onset of fever in a case
or Non-household members with greater than or equal to 3 hours
of contact less than 2 meters (or less than 6.5 feet) away
from a case with rash.
Because of the high case fatality rate and severity
of smallpox, individuals exposed to smallpox virus are
at high risk for developing and transmitting smallpox
and are therefore recommended
to receive ACAM2000 vaccination unless they are not expected
to benefit from smallpox vaccination due
to severe immunodeficiency.
Vaccination with ACAM2000 should be avoided regardless
of smallpox exposures in individuals
with severe immunodeficiency who are not expected to benefit
from the vaccine due to the high likelihood
of a poor immune response
and increased risk for adverse events.
These individuals include bone marrow transplant recipients
within 4 months of transplantation,
persons infected with HIV with CD4 cell counts less
than 50 cells per cubic millimeter,
and persons with severe combined immunodeficiency,
complete DiGeorge syndrome,
and other severely immunocompromised states
requiring isolation.
Of note, CD4 cell counts should be adjusted
for children less than 13 years old.
Instead, these individuals should be given clear
information about the signs and symptoms of smallpox for self-
assessment, provided with specific information on when
and where to seek care if symptoms occur,
and advised to avoid contact with individuals with smallpox
and those recently vaccinated with ACAM2000.
If symptoms of smallpox do occur,
then the individual should be isolated immediately.
Although individuals with severe immunodeficiency may not benefit
from vaccination, if antivirals are not immediately available it
is reasonable to consider the use
of a replication-deficient vaccine such as Imvamune,
if the vaccine is available and authorized for use by the Food
and Drug Administration.
Depending on the magnitude of the outbreak
and the effectiveness of the public health response,
individuals at high risk for developing smallpox infection
without a known smallpox exposure will be defined
by public health authorities during the smallpox emergency
and should be screened for relative contraindications prior
to ACAM2000 vaccination.