Dr. Cherer's analysis of universal antenatal pertussis vaccination.

1. S U P P O R T I N G U N I V E R S A L
A N T E N A T A L P E R T U S S I S
V A C C I N A T I O N
D R . A L L E N C H E R E R

2. Pertussis (Whooping Cough) is a serious health
issue, especially in the very young infant. It is
caused by a bacteria, Bordetella pertussis, and is
transmitted person to person via aerosol
droplets usually by coughing or sneezing. The
illness typically begins with cold-like symptoms
which may then progress to the characteristic
paroxysms of cough terminating with an
inspiratory whoop.

3. In young infants, the illness can proceed to
cyanosis, severe respiratory fatigue, apnea, and
even death. Although whole-cell and acellular
vaccine formulations against B. pertussis are
available, primary immunization generally does
not start until 6-8 weeks and as late as 3 months
of age in some countries, leaving the infant
unprotected during a most vulnerable period.

4. The incidence of pertussis has steadily
increased in the United States and elsewhere
since the 1980s and especially since 2005. Since
2010, 10-50,000 cases of whooping cough have
been reported each year in the United States
with every state represented. More than 48,000
cases were reported in 2012, and in California
alone, greater than 10,000 cases were reported
in 2014.

5. Although all ages are affected, the highest rates
of disease and hospitalization occur in infants
less than one year of age. The numbers have
been accompanied by an alarming increase in
the number of deaths, almost exclusively
among infants less than 3 months of age.

6. One of the causes thought to explain the
resurgence of pertussis is the rapid waning of
the immunity induced by current vaccines.
Prior to the 1990s, a whole-cell vaccine was used
and the immunity it induced was longer lasting.
Since then, acellular pertussis vaccines have
been used exclusively in the United States
primarily due to less frequent adverse reactions.

7. However, these vaccines have been shown to
induce immunity which wanes rapidly over a
period of several years. As a result, pertussis
immunization is required more frequently and the
likelihood of non-protection is much greater,
especially for older children and adults. This is
particularly alarming since such persons are often
the caretakers and closest contacts of young
infants. Thus, when considering prevention
strategies for pertussis, it is critical to include
approaches that prevent pertussis transmission to
young infants.

8. In 2001, the Global Pertussis Initiative (GPI) was
established in response to the resurgence of
pertussis and in an effort to raise global awareness
about pertussis and to develop evidence-based
recommendations for vaccination strategies . Over
the years, the GPI has focused particular attention
on protection of the very young infant and has
emphasized as a primary strategy maternal
immunization during pregnancy which directly
protects the infant through the passive transfer of
pertussis antibodies from mother to fetus.

9. Numerous studies have demonstrated that a
pregnancy booster (Tdap) provides the necessary
protection to the very young from birth until
infant-generated immunity is achieved from the
primary series of pertussis immunizations. Based
on studies that demonstrate robust maternal
antibody production within 2 weeks of booster
immunization and ready immunoglobulin transfer
after 30 weeks’ gestation, current
recommendations call for Tdap immunization
between 28 and 38 weeks’ gestation.

10. Since maternal antibody levels decline
significantly I year post immunization and are
almost non-existent 2 years post immunization,
the Advisory Committee on Immunization
Practices (ACIP) of the Centers for Disease Control
and Prevention (CDC) in 2012 recommended
booster immunization during every pregnancy. To
date, research finds that vaccination against
pertussis during pregnancy is well tolerated and
not associated with any adverse obstetric, birth, or
neonatal outcomes.

11. Recently, a study from the United Kingdom
evaluating antenatal booster immunization and
efficacy in preterm births demonstrated with a
mean gestational age of 29 weeks at time of
immunization and birth at a mean gestation of 32
weeks, protective antibody levels were found at
the start of the primary immunization series.

12. Unfortunately, despite strong recommendations
by the CDC, the American College of Obstetrics
and Gynecology, the American Academy of Family
Physicians, and the American Academy of
Pediatrics , pertussis immunization rates during
pregnancy remain very low. Clearly, education of
caregivers and patients must be a goal. Until a
new pertussis vaccine with longer duration of
protection is available, large-scale pertussis
outbreaks will continue and the burden of disease
will continue to be particularly felt by the very
young infant.

13. drallencherer.net