First RSV Vaccine On The Horizon—Pfizer Touts Strong Trial Results As Children’s Hospitals Count Soaring Cases

Topline

Pharma giant Pfizer on Tuesday said it would ask regulators to greenlight a vaccine designed to protect infants against respiratory syncytial virus, or RSV, following strong results in late-stage clinical trials, a potential gamechanger in efforts to combat the common but potentially lethal infection as cases soar and children’s hospitals struggle to cope.

Pfizer announced strong clinical trial results for its RSV vaccine, which could be the first … [+] approved in the U.S.

Future Publishing via Getty Images

Key Facts

Pfizer plans to ask the Food and Drug Administration to authorize an RSV vaccine designed to protect infants by the end of the year, the company said, citing strong results from late-stage clinical trials.

A single shot given during the late second to third trimester of pregnancy was highly effective at protecting newborns during their first months of life, the company said.

The shot was nearly 82% effective at preventing a severe form of lower respiratory tract illness from RSV during the baby’s first 90 days of life, Pfizer said, and about 70% effective over the first six months.

The vaccine also cut the number of doctors visits due to respiratory illness caused by RSV by an average of more than 50% compared to a placebo, Pfizer said, noting that while this failed to meet its target outlined at the start of the trial it still considered the result clinically meaningful.

The trial followed around 7,400 pregnant people and their newborns from 18 different countries from June 2020—infants were followed for at least a year after birth and half were followed for two—which spanned multiple RSV seasons in both north and southern hemispheres, Pfizer said.

No safety concerns for parents or children were identified during the trial and the vaccine was well-tolerated, Pfizer said, adding that it plans to submit the results for peer review in a scientific journal and will seek approval from additional regulators in the “coming months.”

News Peg

Children’s hospitals across the U.S. are struggling to cope with a large surge of RSV infections, which had decreased during the Covid-19 pandemic. The spike in infections, while not unusual, has come unseasonably early and is particularly severe and alongside a rise in other infections like Covid-19 and the flu hospitals are feeling the strain.

What To Watch For

If approved, Pfizer’s vaccine will be the first shot to protect against RSV on the market. Pfizer is also investigating the shot’s potential in older adults, who are also at risk from RSV, and in August said trials showed it to be effective in this group. Pfizer is one of a number of pharmaceutical firms including Moderna, Johnson & Johnson and GlaxoSmithKline pushing to develop an RSV vaccine, which has eluded scientists for decades, although most of these focus on older adults. GlaxoSmithKline is close behind Pfizer and is expected to seek regulatory approval in the near future after announcing promising trial results in October.

Key Background

RSV is a common respiratory virus that is easily shrugged off by most people. It can cause mild, cold-like symptoms including runny nose, coughing, sneezing, decreased appetite and fever, according to the CDC, and is so common the agency says “virtually all children” have had an RSV infection by the time they reach two years of age. For very young infants, older adults and people with compromised immune systems, however, RSV can be deadly and can also trigger more serious infections like pneumonia. It is the biggest killer of young infants worldwide after malaria, kills between 100 and 300 children under five in the U.S. each year and is responsible for 14,000 deaths in adults aged 65 and over every year in the U.S. There are no specific treatments or vaccines and experts recommend hand washing and sanitizing surfaces as some of the best ways to prevent infection, which is passed through coughs and sneezes and can linger on surfaces for hours.

Topline

Key Facts

News Peg

What To Watch For

Key Background

Further Reading