New research shows that vaccinating pregnant women helped protect their newborns from the common but scaryHe Each falls with wheezing children. Preliminary results give hope that after decades of failure and frustration, vaccines against RSV may eventually take off.
Pfizer announced Tuesday that a large international study found that the vaccination of mothers-to-be was about 82% effective in preventing severe cases of RSV for their babies in the first 90 days of life. At 6 months of age, the vaccine was still proving to be 69% effective against severe disease – and there were no signs of safety problems in either the mothers or the babies.
“Moms are always passing their antibodies to their baby,” said virologist Kena Swanson, Pfizer’s vice president of viral vaccines. The “vaccine just puts them in that better position” to create and pass on RSV-fighting antibodies.
Vaccine discovery isn’t just about protecting babies. RSV is dangerous even for older adults, and both Pfizer and rival GSK recently announced that their competitive shots have proven to be protective for seniors as well.
None of the findings will help this year when aChildren’s hospitals are already crowded. But they raise the possibility that one or more vaccines may be available before next fall’s RSV season.
“My fingers are crossed,” said Dr. William Schaffner, an infectious disease specialist at Vanderbilt University. “We are infiltrating.”
Tuesday’s data was reported in a press release and was not scrutinized by independent experts.
Cases of RSV are rising rapidly among young children, who usually contract the virus by the age of three, but who were protected from it and other viruses.lockdown period.
“Pediatric ICUs across the country, many parts of it, are full,” said CBS News medical contributor Dr. David Agus. He said most hospitalizations now deal with influenza and RSV and not COVID-19.
Cases of three different viruses rise simultaneously as more professionals are leaving the health care sector for work that either pays better or is less physically and emotionally draining, leading to the nation’s strained health care system. may be at further risk.
“I worry that hospitals, health care providers, are going to be overwhelmed,” said Dr Celine Gounder, a medical contributor to CBS News and editor-at-large of Kaiser Health News. “We’re seeing very high rates of both flu and RSV, so maybe something like about 35,000 hospitalizations per week from those two conditions.”
Here’s a look at the long search for RSV vaccines.
What is RSV?
For most healthy people, RSV, or respiratory syncytial virus, is a cold-like nuisance. But for the very young, the elderly, and people with certain health problems, it can be serious, even life-threatening. The virus can infect deep into the lungs, causing pneumonia, and in infants it can inflame the small airways and make breathing difficult.
In the US, approximately 58,000 children under the age of 5 are hospitalized for RSV each year and several hundred die. Among adults 65 and older, approximately 177,000 are hospitalized with RSV and 14,000 die annually.
Worldwide, RSV kills about 100,000 children a year, mostly in poor countries.
Why is there no vaccine?
In the 1960s, a tragedy shook the entire region. Using the approach that led to the first polio vaccine, scientists created an experimental RSV vaccine by growing and killing the virus in a laboratory. But testing in children found that not only was the vaccine not protective, the condition of young people who caught RSV after vaccination was worse. Two died.
“For a period of 20 years, even though the science was advancing, no one wanted to get close to the development of the RSV vaccine,” Schaffner said.
He said that today’s modern RSV vaccine candidates had previously been tested in older adults, not children.
What brought development back on track?
Modern vaccines target the outer surface of a virus, what the immune system sees when a germ invades. For RSV, that target is the so-called F protein that helps the virus reach human cells. Again there was a hurdle: that protein is a shape-shifter, rearranging its form before and after it “fuses” the cells.
It turns out that the immune system makes effective anti-RSV antibodies only when it spots a pre-fusion version of that protein, explained structural biologist Jason McClellan of the University of Texas at Austin.
In 2013, McClellan and virologist Barney Graham were working at the National Institutes of Health when they built a house in just the right shape and figured out how to freeze it in that form. That discovery opened the way for the development of a variety of experimental RSV vaccine candidates today.
(The same discovery was the key to highly successful COVID-19 vaccines, as the coronavirus is also wrapped in a shape-changing surface protein.)
What’s in the pipeline?
Several companies are making RSV vaccines, but Pfizer and rival GSK are at the forefront. Both companies recently reported end-stage trials in older adults. Competitive vaccines are made somewhat differently but each has been shown to be very effective against particularly severe disease. Both companies plan to seek regulatory approval in the US by the end of the year, as well as in other countries.
The older-adult data “looks fantastic,” said McClellan, who has followed vaccine development closely. “I think we are on the right track.”
And if pregnant women do end up vaccinated, it could be a “two-person win instead of just one,” providing protection to both the unborn mother and the baby, said Dr. Wilbur Chen of the University of Maryland School of Medicine. he said.
Pfizer’s maternal vaccine is the same recipe it successfully tested in older adults — and it also plans to seek Food and Drug Administration approval for those vaccinations by the end of the year.
The new study included 7,400 pregnant women in 18 countries, including the US, and spanned multiple RSV seasons. Preliminary results reported on Tuesday suggest the vaccine was most effective against severe disease. For mild disease, the effectiveness was 51% to 57%—less than the study’s statistical requirements but the result is that Pfizer is still considered clinically meaningful because it can mean fewer trips to the doctor’s office.