The US Food and Drug Administration has approved Pfizer’s respiratory syncytial virus (RSV) vaccine for use in women during the middle of the third trimester of pregnancy – to protect their babies.
Some experts, however, have raised concerns over the higher number of pre-term births among those who received the vaccine in the clinical trial, compared with pregnant women in the placebo group.
The jab can be given to women 32 to 36 weeks into a pregnancy to prevent lower respiratory tract infection and severe disease in infants until they are six-months-old, the company said.
Reuters reports that three months ago, an FDA panel of outside experts backed the safety and effectiveness of the RSV vaccine for women in their second and third trimesters.
A Pfizer spokesperson could not comment on the FDA’s reasoning for the more limited window for administering the vaccine, but said the company was confident the shot would have a positive impact on public health and RSV rates.
The vaccine, sold under the brand name Abrysvo, is already approved for those aged 60 and older to block infection from the disease that kills around 160 000 people globally each year.
Infants are at greatest risk for severe illness from RSV. An estimated 58 000 to 80 000 under-fives are admitted to hospital annually with RSV infection in America.
The approval of the vaccine will make it the first ever maternal shot against RSV widely available in the US.
The FDA’s decision was based on data from a late-stage trial with more than 7 000 participants showing the vaccine to be 82% effective in preventing severe infections in infants when given to expecting mothers in the second half of their pregnancy.
The most common side effects in the women were fatigue, headache, pain at the injection site, muscle pain, nausea, joint pain and diarrhoea.
In July, Sanofi and partner AstraZeneca in July received approval of their antibody therapy, nirsevimab, to prevent lower respiratory tract disease in infants and toddlers, while in May, the FDA had also approved to GSK’s RSV vaccines for older adults, helping it and Pfizer seal their presence in a multibillion-dollar market.
GSK is not seeking approval for its shot in pregnant women.
Reuters article – US FDA approves Pfizer’s maternal RSV vaccine to protect infants (Open access)
See more from MedicalBrief archives:
Pfizer’s RSV vaccine for older adults approved by FDA
FDA panel green-lights RSV pregnancy jab, but concerns persist
Pfizer to apply for approval of first maternal RSV vaccine
First RSV jab for adults approved by FDA