From the Journals

Pertussis vaccine at birth shows immune response, tolerability

 

Key clinical point: A monovalent acellular pertussis vaccine dose at birth appears safe, tolerable, and effective.

Major finding: 93% of 212 newborns receiving an acellular pertussis vaccine at birth showed antibodies against pertussis toxin and pertactin at 10 weeks, compared with 51% of 205 newborns without the birth dose.

Study details: The findings are based on a randomized controlled trial involving 417 healthy term newborns in four Australian cities from June 2010 to March 2013.

Disclosures: The research was funded by an Australian National Health and Medical Research Council (NHMRC) grant, and several authors received NHMRC grants. One author also was supported by a Murdoch Children’s Research Institute Career Development Award. GlaxoSmithKline provided the vaccine and conducted the serologic assays. The authors reporting having no conflicts of interest.

Source: Wood N et al. JAMA Pediatr. 2018 Sep. 10. doi: 10.1001/jamapediatrics.2018.2349.

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Pertussis vaccination at birth vs. the maternal immunization strategy

Pertussis is most likely to cause morbidity or kill neonates between birth and when they are given their first pertussis vaccine at 6-8 weeks of age. This is well known.

In the current study giving the acellular pertussis (aP) vaccine at birth led to “significantly higher antibody titers to pertussis antigens at 10 weeks of age,” compared with those who did not receive it. Those infants who received the birth dose of aP vaccine also had higher pertussis antibodies at 6 weeks, whether or not their mothers had received Tdap within 5 years prior to delivery.

When this study began in 2009, maternal immunization was not a well accepted concept, but this attitude has changed, in part due to the safe vaccination of pregnant women with the pandemic flu vaccine. Despite this, Centers for Disease Control and Prevention 2016 data showed that only 49% of pregnant women in the United Stated received Tdap. These rates need to increase.

Administering the aP vaccine with the existing hepatitis B vaccine at birth to infants whose mothers who did not receive Tdap during pregnancy would be a practical solution, if the aP vaccine were universally available.

But the aP vaccine currently is not available in the United States and many other countries as a standalone vaccine, and the administration of DTaP as a birth dose has been linked with “significant immune interference.” The aP vaccine could have a place in countries where it is available, and there is no maternal immunization program. Otherwise, boosting maternal immunization appears to be the primary approach for now.

Kathryn M. Edwards, MD, is the Sarah H. Sell and Cornelius Vanderbilt Chair in Pediatrics at Vanderbilt University, Nashville. She specializes in pediatric infectious diseases. These comments are a summary of her editorial accompanying the article by Wood et al. (Pediatrics. 2018 Sep 10. doi: 10.1001/jamapediatrics.2018.2363). Dr. Edwards said she had no conflicts of interest.


 

FROM JAMA PEDIATRICS

Nearly all newborns who received an acellular pertussis-only vaccine at birth showed titers for pertussis and no difference in adverse events, compared with a group receiving only the hepatitis B vaccine, a randomized clinical trial from Australia has found.

Pertussis copyright Jacopo Werther/Wikimedia Commons/Creative Commons Attribution 2.0

“These results indicate that a birth dose of aP vaccine is immunogenic in newborns and significantly narrows the immunity gap between birth and 14 days after receipt of DTaP at 6 or 8 weeks of age, marking the critical period when infants are most vulnerable to severe pertussis infection,” reported Nicholas Wood, PhD, of the National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases in New South Wales, Australia, and his colleagues.

“Administration of the acellular pertussis vaccine at birth has the potential to reduce severe morbidity from Bordetella pertussis infection in the first 3 months of life, especially for infants of mothers who have not received a pertussis vaccine during pregnancy,” the researchers concluded in JAMA Pediatrics.

The researchers enrolled 417 infants from Sydney, Melbourne, Adelaide, and Perth between June 2010 and March 2013 and randomized them to receive either the hepatitis B vaccine alone (n = 205) or the hepatitis B vaccine with a monovalent acellular pertussis vaccine (n = 212) within the first 5 days after birth. The randomization was stratified for mothers’ receipt of the Tdap before pregnancy.

The Centers for Disease Control and Prevention currently recommends all newborns receive the hepatitis B vaccine shortly after birth and that pregnant women receive the Tdap vaccine during each pregnancy. There is not currently a monovalent acellular pertussis vaccine licensed in the United States.

The study infants then received the hexavalent DTaP-Hib-hep B-polio vaccine and the 10-valent pneumococcal conjugate vaccine at 6 weeks, 4 months, and 6 months.

The primary outcome was detectable levels of IgG antibody to pertussis toxin and pertactin at 10 weeks old.

Of the 206 infants receiving the pertussis vaccine at birth, 93% had detectable antibodies to pertussis toxin and pertactin at 10 weeks, compared with 51% of the 193 infants who received only the hepatitis B shot (P less than .001). Geometric mean concentration for pertussis toxin IgG also was four times higher in infants who received the pertussis vaccine at birth.

Adverse events were similar in the two groups both at birth and at 32 weeks, demonstrating that the pertussis birth dose is safe and tolerable.

“More important, in this study, the prevalence of fever after receipt of the birth dose, which can mistakenly be associated with potential sepsis and result in additional investigations in the neonatal period, was similar in both the group that received the aP vaccine at birth and the control group,” the authors reported.

A remaining question is the potential impact of maternal antibodies on protection from pertussis.

“The presence of maternal pertussis antibodies at birth can negatively affect postprimary responses to pertussis, diphtheria, and diphtheria-related CRM197 conjugate vaccines with a variety of infant immunization schedules and vaccines,” the authors noted. “The clinical significance of reductions in pertussis antibody related to maternal interference will require ongoing clinical evaluation, because there are no accepted serologic correlates of protection.”

The research was funded by a Australian National Health and Medical Research Council (NHMRC) grant, and several authors received NHMRC grants. One author also was supported by a Murdoch Children’s Research Institute Career Development Award. GlaxoSmithKline provided the vaccine and conducted the serologic assays. The authors reported having no conflicts of interest.

SOURCE: Wood N et al, JAMA Pediatr. 2018 Sep 10. doi: 10.1001/jamapediatrics.2018.2349.

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