Pneumococcal Vaccines Safe for Pregnant Women With HIV

By Marilynn Larkin

May 12, 2021

NEW YORK (Reuters Health) - Pneumococcal vaccines PCV-10 and PPV-23 are equally safe and immunogenic in pregnant women with HIV, although PPV-23 administration might be more beneficial because it includes a wider range of serotypes, researchers say.

"There is conflicting information regarding the responses to the two vaccines in people with HIV," Dr. Adriana Weinberg of the University of Colorado Anschutz Medical Campus in Aurora told Reuters Health by email. "Importantly, the polysaccharide vaccine confers protection against up to 23 different types of pneumococci, whereas the conjugated vaccines confer protection against up to 10 (PCV 10, used in Brazil and some European countries) or up to 13 types (PCV 13, used in the U.S. and other countries)."

"In some countries, including the U.S., there is a formal recommendation to administer both to people with HIV, starting with the conjugated vaccine and followed by the polysaccharide vaccine eight weeks or more later," she said.

Disadvantages to that strategy, she said, include "a delay in administering the polysaccharide vaccine, which is the one that really counts in the current landscape of pneumococcal infection, and the conjugated vaccine is expensive, which adds to the financial burden on the health care system."

"We showed that there were biologically insignificant differences in the amount of antibodies that crossed the placenta in response to the two vaccines such that (they both) conferred similar levels of protection to the neonates," she said. "The levels of protection in infants born to vaccinated mothers were much higher compared to infants born to mothers who received placebo, but were short-lived."

As reported in The Lancet HIV, the double-blind, multicenter, randomized controlled trial in Brazil enrolled 347 pregnant women with HIV who were randomly assigned to PCV-10, PPV-23, or placebo. At study entry, pregnancy durations ranged from 14 weeks to less than 34 weeks and participants were taking antiretroviral therapy.

In the first four weeks, the frequency of grade 3 or higher adverse events was similar in the vaccine and placebo groups (3% PCV-10, 2% for PPV-23, and 3% for placebo); however, injection site and systemic grade 2 adverse reactions were more frequent in the vaccine groups (14% for PCV-10, 7% for PPV-23, and 3% for placebo).

Nonetheless, overall, the frequency of such events was similar across maternal treatment group (20% for PCV-10, 21% for PPV-23, and 20% for placebo).

At four weeks post-vaccination, 65% of women in each vaccine group and no women in the placebo group had seroresponses against five or more serotypes. Seroresponse differences of 20% or higher in vaccine compared with placebo recipients persisted up to 24 weeks postpartum.

At birth, 67% of infants in the PCV-10 group, 57% of the PPV-23 group, and 17% of the placebo group had seroprotection against five or more serotypes.

However, by eight weeks, seroprotection in the infants had waned to 19% in the PCV-10 group, 23% in the PPV-23 group, and 1% in the placebo group.

Overall, as Dr. Weinberg indicated, both vaccines were equally safe and immunogenic in pregnant women with HIV, although PPV-23 included a broader range of serotypes.

Therefore, Dr. Weinberg said, "Our findings do not support the administration of pneumococcal conjugated vaccines to pregnant women with HIV and question the need to administer this vaccine to young adults with HIV in general. It is unclear how much protection maternal vaccination may confer to the infant, because our study was too small to determine the efficacy of this strategy for pneumococcus."

Dr. Joseph Alvarnas, a hematologist-oncologist at City of Hope in Duarte, California, commented on the study in an email to Reuters Health. "We should approach these findings with cautious optimism," he said. "While the statistical power of the study is limited, it demonstrates that both pneumococcal vaccines could be administered with safety and with clear evidence of post-immunization development of anti-pneumococcal antibodies in the vaccinated population and their infants following birth."

"The study was not sufficiently powered to detect any efficacy differences between the vaccines (and) was also underpowered to look at the impact of virological control/T-cell reconstitution upon response to the vaccine," he noted. "It is important to recognize that infant antibody levels declined in a relatively short period of time and that vaccination in this setting is not a substitute for standard infant support strategies."

"Peripartum vaccination should be considered as part of a risk-reduction and comprehensive care strategy for HIV-infected women," he said. "It is far less clear whether the development of immunization-related antibodies reduced the risk of subsequent infection in the study subjects."

SOURCE: Lancet HIV, online April 26, 2021.