| Polio |
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What is the current status of polio in the
world? |
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| Since the Global
Polio Eradication Initiative was launched in
1988, the number of polio cases worldwide has
declined by more than 99.99%. Among the three
wild poliovirus (WPV) serotypes, only type 1
(WPV1) has been detected since 2012. Global
eradication of type 2 WPV was declared in
2015; type 3 WPV was declared eradicated in
2019. The number of detected WPV1 cases has
reached a historic low (33 cases in 2018 and
176 in 2019) in the last two countries with
endemic WPV1 transmission (Afghanistan and
Pakistan). |
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| This decline in
polio cases worldwide is attributable
primarily to use of the live, attenuated oral
poliovirus vaccine (OPV) in national routine
immunization schedules and mass vaccination
campaigns. The success and safety record of
OPV use is offset by the rare emergence of
genetically divergent vaccine-derived
polioviruses (VDPVs), whose genetic drift from
the parental OPV strains indicates prolonged
replication or circulation. Circulating VDPVs
(cVDPVs) can emerge in areas with low
immunization coverage and can cause outbreaks
of paralytic polio. In addition,
immunodeficiency-associated VDPVs (iVDPVs) can
emerge in persons with primary
immunodeficiencies and can replicate and be
excreted for years. During January 2018–March
2020 new cVDPV outbreaks were confirmed in 26
countries; of those, cVDPV2 strains were the
most frequently detected, causing 547 cases in
21 countries. |
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| After the
emergence of multiple cVDPV2 outbreaks during
the preceding 15 years, in April 2016, all OPV-using countries switched from using trivalent
OPV (tOPV; Sabin types 1, 2, and 3) to
bivalent OPV (bOPV; Sabin types 1 and 3). To
control and prevent cVDPV2 outbreaks,
approximately 100 million
doses of monovalent type 2 OPV (mOPV2) have
been distributed in affected countries: in
addition, a novel monovalent type 2 OPV
(nOPV2) that is less
likely to produce cVPDV disease is in the
final stages of preparation to replace the
current mOPV2. To maintain protection from
poliovirus type 2 paralysis,
176 OPV-using countries have introduced at
least 1 dose of injectable inactivated polio
vaccine (IPV) beginning in 2015. Additional
information about the
polio eradication program is available on the
CDC website at
www.cdc.gov/polio. |
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What is the routine schedule for giving IPV (IPOL,
Sanofi Pasteur) to children? |
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| In the U.S., all
infants and children should receive 4 doses of
IPV at ages 2, 4, 6–18 months, and 4–6 years.
The first dose may be given as early as 6
weeks of age. The final dose should be
administered at 4 years of age or older, regardless of the number of previous doses,
and should be given 6 months
or more after the previous dose. A fourth dose
in the routine IPV series is not necessary if
the third dose was given at 4 years of age or
older and 6
months or more after the previous dose. |
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| Infants and
children traveling to areas where there has
been wild or vaccine-derived poliovirus
circulation in the last 12 months should be
vaccinated
according to the routine schedule. If the
routine series cannot be administered within
the recommended intervals before protection is
needed, an
accelerated schedule can be used: 1) the first
dose should be given to infants 6 weeks of age
and older, 2) the second and third doses
should be
administered at 4 weeks or more after the
previous doses, and 3) the minimum interval
between the third and fourth doses is 6
months. If the age-appropriate series is not completed before
departure, the remaining IPV doses to complete
a full series should be administered when
feasible, at the
intervals recommended for the accelerated schedule. If doses are needed while residing
in the affected country, the polio vaccine
that is available (IPV or
oral polio vaccine) may be administered. |
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| What is the
schedule for older children who have not
completed their IPV series? |
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| The schedule for
polio vaccination for unvaccinated or
under-vaccinated older children through age 17
years is 2 doses of IPV separated by 4–8
weeks,
and a third dose 6–12 months after the second
dose. If an accelerated schedule is needed,
the child should receive two doses separated
by at least 4
weeks and a third (final) dose given at least
6 months after the second dose. Polio vaccine
is not routinely administered to U.S.
residents age 18 years
and older. |
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| Should adults
get vaccinated against polio? |
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| Routine polio
vaccination of U.S. residents 18 years of age
and older—including those working in
healthcare or in healthcare-related
training—is not
recommended. Polio vaccination is recommended
for all travelers to countries with wild
poliovirus (WPV) or vaccine-derived poliovirus
(VDPV) circulation.
Countries are considered to have WPV or VDPV
circulation if they have evidence during the
previous 12 months of ongoing endemic
circulation (WPV
only), a polio outbreak, or environmental
evidence (through sewage sampling) of WPV or
VDPV circulation. For additional information
on countries with
WPV or VDPV circulation and vaccine
recommendations, consult the travel notices on
the CDC Travelers' Health website (wwwnc.cdc.gov/travel/notices)
or the weekly update of reported WPV and VDPV
cases at the Global Polio Eradication
Initiative website
(www.polioeradication.org/Dataandmonitoring/Poliothisweek.aspx). |
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Adults who are
traveling to areas where WPV or VDPV is
actively circulating and who are unvaccinated, incompletely vaccinated, or whose vaccination
status is unknown should receive a total
series of 3 doses: 2 doses of IPV administered
at an interval of 4–8 weeks; a third dose
should be administered
6–12 months after the second. If 3 doses of IPV cannot be administered within the
recommended intervals before protection is
needed, the following
alternatives are recommended:
- If more than 8
weeks is available before protection is
needed, 3 doses of IPV should be
administered at least 4 weeks apart.
- If less than 8 weeks but more than 4
weeks is available before protection is
needed, 2 doses of IPV should be administered at least 4 weeks
apart.
- If less than 4 weeks is available before
protection is needed, a single dose of IPV
is recommended.
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| If less than 3
doses are administered, the remaining IPV
doses to complete a 3-dose series should be
administered when feasible, at the intervals
recommended above, if the person remains at
increased risk for poliovirus exposure. |
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| If an adult at
risk previously received only one or two
documented doses of polio vaccine (either OPV
or IPV), he or she should receive the
remaining
dose(s) of IPV, regardless of the interval
since the last dose. It is not necessary to
restart the vaccination series. |
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| Adults who have
completed a routine series of polio vaccine
are considered to have lifelong immunity to poliomyelitis, but data on duration of
immunity are
lacking. As a precaution, adults 18 years of
age or older who are traveling to areas where WPV or VDPV is actively circulating and who
have received a
routine series with either IPV or OPV in
childhood should receive another dose of IPV
before departure. For adults, available data
do not indicate the need
for more than a single lifetime booster dose
with IPV. Note: the World Health Organization recommends that countries affected by wild
poliovirus or cVDPV
outbreaks require residents and long-term (4 weeks or more) visitors show proof of polio
vaccination before leaving the country. These
recommendations
are regularly reviewed and updated. Visit
CDC's Travelers' Health site for current
details about country-specific requirements (wwwnc.cdc.gov/travel/). |
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| We have an
adult who was diagnosed with polio as a child
with some residual effects. This adult will be traveling overseas and the CDC travel website
recommends a dose of polio vaccine. Should he
be vaccinated with polio vaccine even though
he had polio in the past? |
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| Immunity to one
of the serotypes of polio does not produce
significant immunity to the other serotypes. A
history of having recovered from polio disease
should not be considered evidence of immunity
to polio. It would be appropriate to vaccinate
this adult if he will be traveling to an area
for which polio
vaccination is recommended. |
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| Please
describe the CDC recommendations for polio
vaccination for infants, children, and adults traveling to and from countries affected by
wild or
vaccine-derived poliovirus. |
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| CDC recommends
that all travelers to countries affected by
wild or circulating vaccine-derived poliovirus
(cVDPV) be vaccinated fully against polio.
Adults
who were fully vaccinated during childhood
should receive an additional (single) lifetime
booster dose of polio vaccine. |
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| The World Health
Organization additionally recommends that
countries affected by wild poliovirus or cVDPV
outbreaks require residents and long-term (4
weeks or more) visitors show proof of polio
vaccination before leaving the country. These
recommendations are regularly reviewed and
updated. Visit
CDC's Travelers' Health site for current
details about country-specific requirements (wwwnc.cdc.gov/travel/). |
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| We frequently
see children (mostly from certain foreign
countries) who have received 6 or more doses
of polio vaccine, all administered before 4
years of
age. How do we handle this when assessing the
child's immunization history? |
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| It is common
practice in many developing countries to
administer oral polio vaccine to children
during both routine visits and periodic
vaccination
campaigns, so a child's record may indicate
more than 4 doses. Some of these doses may not
be valid according to the U.S. immunization
schedule. |
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| Doses are
considered valid if written documentation
indicates that doses of polio vaccine were
given after 6 weeks of age and the vaccine
received was
listed as IPV, trivalent OPV (tOPV) or simply
"OPV", if the "OPV" was administered before
April 1, 2016 and not noted as given during a
vaccination
campaign. |
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| Why is this? Only
trivalent polio vaccine doses count as valid
for the U.S. polio vaccination schedule.
Trivalent OPV ceased to be used globally in
April
2016. OPV administered before April 1, 2016,
generally was tOPV. However, OPV doses noted
as given during a vaccination campaign do not
count as
valid because such campaigns may have used
monovalent or bivalent OPV. |
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| If the history is
of a complete series of IPV, at least one dose
should be administered on or after 4 years of
age and at least 6 months after the previous
dose. If a complete series cannot be
identified that meets these criteria, then the
child should receive as many doses of IPV as
needed to complete the
U.S. recommended schedule. |
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| How do I
determine if doses of polio vaccine
administered outside the United States were
trivalent OPV? |
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| Use the date of
administration to make a presumptive
determination of what type of OPV was
received. Only trivalent doses count as valid
for the U.S. polio
vaccination schedule. |
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| Trivalent OPV was
used throughout the world before April 2016.
In April 2016, all countries using OPV
switched to bivalent OPV (bOPV). In addition,
some
countries also use monovalent OPV (mOPV)
during special vaccination campaigns. Doses
recorded as bOPV or mOPV, or doses noted on an
immunization record as given during a vaccination campaign, do not count as valid
doses for the U.S. polio vaccination schedule. |
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| If the record
indicates OPV, and the dose was given prior to
April 1, 2016, it can be counted as a valid
tOPV dose. If the dose was administered on or
after
April 1, 2016, it should not be counted as a
valid dose for the U.S. polio vaccination
schedule because it was not trivalent. |
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| People younger
than age 18 years with doses of OPV that do
not count towards the U.S. vaccination
requirements should receive IPV doses to
complete
the schedule according to the U.S. polio
immunization schedule. See
www.cdc.gov/mmwr/volumes/66/wr/pdfs/mm6601a6.pdf
for more information on this
issue. |
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| We
occasionally encounter older teen-agers who
received 4 doses of IPV before their fourth
birthday. Should we recommend a 5th dose of IPV for these
children? |
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| Yes. ACIP revised its recommendation for IPV in June 2009 to include a dose at 4 through 6 years regardless of the number of doses prior to age 4 years. You might want to check with your state immunization program or immunization registry manager to see what they accept/expect. Contact information for state immunization managers can be found at www.immunize.org/coordinators. |
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| If an
immigrant infant has a record of 1 or 2 doses
of OPV in their country of origin how many
more doses of IPV should be given? |
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| Polio vaccine
given outside the United States is valid if
written documentation indicates that all doses
were given after 6 weeks of age and the
vaccine
received was IPV or trivalent OPV (tOPV). No
doses of OPV given since April 1, 2016, count
toward the U.S. polio vaccination schedule.
See the prior
question for details on assessment of OPV
doses by the date of administration. |
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| If both tOPV and
IPV were or will be administered as part of a
series, the total number of doses needed to complete the series is the same as that
recommended for the U.S. IPV schedule. If the
child is younger than 4 years of age a total
of 4 doses of polio vaccine are recommended.
If the child is
currently 4 years of age or older, a total of
3 doses completes the series. A minimum
interval of 4 weeks should separate doses in
the series, with the final
dose administered on or after the fourth
birthday and at least 6 months after the
previous dose. If only tOPV was administered,
and all doses were given
before 4 years of age, 1 dose of IPV should be
given at 4 years of age or older, at least 6
months after the last tOPV dose. |
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| Our
23-year-old patient has been accepted to a
physician assistant program that requires
polio vaccine for all students. She has 2
documented doses of
oral polio vaccine (OPV) as a child, then
recently had a dose of inactivated polio
vaccine (IPV). How many more doses of IPV does
she need to complete
the series and on what schedule? |
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| U.S. residents 18
years and older generally do not require polio
vaccination. However, in this case the person
is required to have evidence of vaccination
for a medical training program. People who
receive a mixed series of OPV and IPV should
receive a total of either 3 or 4 doses
depending on the age at
the time of the last dose. In this case the
recent dose of IPV can be counted as the third
and final dose in the series. The minimum
interval between the
next-to-last and last doses in the polio
vaccination series is 6 months and the last
dose should be at age 4 years or older. |
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| Is it true
that IPV can be given either SC or IM? |
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| Yes. |
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| What is the
risk of serious reactions following IPV? |
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| There are no
severe reactions known to occur following IPV. |
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ACIP Recommendations
Vaccine Information Statements 
