Topline
A panel of independent experts on Thursday recommended the Food and Drug Administration approves a Pfizer RSV vaccine designed to protect babies by vaccinating pregnant parents, potentially paving the way for babies’ first RSV shot — weeks after the agency announced the country’s first shot for the common but potentially deadly infection.
Main facts
The FDA panel voted unanimously (14-0) on the effectiveness of the drug, and 10 of the 14 members of the advisory board voted that the vaccine — known as Abrysvo — is safe, with some members saying a slightly higher rate of preterm birth among vaccine recipients.
RSV, which stands for respiratory syncytial virus, is a common respiratory infection that usually causes mild illness in healthy adults, but can cause serious, potentially fatal illness in younger children, older adults, and those with underlying medical problems.
Because protective antibodies can be transferred from mother to developing fetus, the maternal shot, which is given to pregnant people between 24 and 36 weeks of pregnancy, also protects children in their first months of life.
Evidence from Pfizer’s late-stage clinical trial, involving nearly 7,400 pregnant people, indicated that the injection was 82% effective in preventing serious illness during the first three months after birth and 69% during pregnancy. first six months.
The injection was also 51% effective in preventing doctor visits for RSV-related illness within the first six months of life, the study found.
Safety data for the injection is also “generally favorable,” the FDA said in a briefing documents released prior to the meeting, with relatively standard reported side effects such as injection site pain, myalgia and headache.
What to watch out for
The FDA has yet to approve the vaccine, and a decision is likely months away. The agency is not required to follow its advisors’ recommendations, but almost always does, and the panel’s decision will carry significant weight. Moving on, Pfizer is also seeking FDA approval for its RSV injection for use in older adults. A number of other companies are also completing late-stage trials for their own injections, and the FDA is reviewing an antibody injection to protect infants against RSV that is being jointly developed by European pharmaceutical heavyweights Sanofi and AstraZeneca. The European Union regulator, the European Medicines Agency, has already approved the preventive injection.
What we don’t know
The analysis in its briefing revealed that the FDA was eager to hear its advisors’ views on the number of preterm births observed in Pfizer’s studies. While the agency’s analysts note that the overall incidence of preterm birth in the study — for both vaccine and placebo recipients — was lower than background rates in all countries where the study was conducted, there was a slightly higher rate among vaccine recipients . This difference, 5.7% in vaccinated pregnant people versus 4.7% in the placebo group (the overall US rate is about 10%), was not statistically significant and it is not clear whether the vaccine played a role. However, the issue is glaring and the prospect of preterm birth will already have been high in the minds of FDA advisers and officials after Pfizer’s rival GlaxoSmithKline (GSK) stopped its own trials of a maternal RSV vaccine after learning of early data Involving premature birth and neonatal death.
News Peg
The FDA approved an RSV injection of GSK in early May. The agency’s green light marked the culmination of decades of scientists’ hard work and followed many setbacks. It also marked a major coup for GSK, whose shot, Arexvy, beat fierce competition from an increasingly crowded field that included the likes of Pfizer, Moderna and Johnson & Johnson. However, if approved, Pfizer’s vaccine will still be an important milestone, as GSK’s vaccine targets older adults ages 60 and older.
Key background
RSV is a common respiratory virus and it infects almost all humans by the time they are two years old. Healthy adults will typically experience nothing but mild, cold-like symptoms such as a runny nose, cough and fever, according to to the CDC, and aside from other health problems, most will recover quickly and easily. However, infection can be more deadly for other groups, especially very young babies, older adults, and people with conditions such as a weakened immune system. RSV can be fatal in such people. Complications from RSV in young children in the US kill between 100 and 300 young children a year and hospitalizes many more. The danger is particularly acute for very young babies, especially in the first months and years of life, as inflammation and mucus caused by the infection can be enough to block already small airways. In the US, RSV is and is a much more serious problem among older adults responsible for 14,000 deaths in people age 65 and older per year.
Surprising fact
After malaria, RSV is the largest killer of young infants worldwide. In 2017, the World Health Organization estimated that RSV results in more than 3 million hospitalizations and nearly 60,000 deaths in children under the age of five each year. Children under six months accounted for nearly half of this figure.
Read further
First RSV vaccine for children – given to pregnant mothers – may arrive months sooner as FDA Fast-Tracks Review (Forbes)
Will a New Wave of RSV Vaccines Stop the Dangerous Virus? (Nature)
First FDA-approved RSV vaccines expected later this year: The best vaccines and their effectiveness (Forbes)