Pfizer has announced that its experimental RSV vaccine is highly effective – a ray of hope for parents and doctors.
The pharma giant announced that its injection may reduce the risk of hospitalization in infants aged up to six months infected with the seasonal virus.
If approved, it would be the first vaccine against RSV, killing between 100 and 500 children under the age of five each year and hospitalizing about 58,000.
That could prove a lifeline for hospitals, which are currently overwhelmed with unusually high cases of the virus – which has been blamed on lockdowns aimed at suppressing child immunity.
The vaccine is given to pregnant women during the late second to third trimester of their pregnancy. Vaccination during pregnancy allows the antibodies to cross to the placenta, protecting the fetus.
Pfizer’s study involved 7,400 pregnant women in 18 countries, who received either one dose of the experimental vaccine or a placebo.
Pfizer expects to complete its application for approval by the Food and Drug Administration by the end of 2022, and potentially grant a federal approval before the next respiratory infection season begins.
The graph above shows the number of positive RSV virus tests by date in the United States. It shows they are now at their highest level since 2020, before the pandemic started. The data comes from the Centers for Disease Control and Prevention
The vaccine’s immune power is transferred to babies in the womb when administered to expectant mothers, giving them crucial protection against the virus for the first 90 days of life.
Administration of the vaccine to expectant mothers has been shown to be nearly 82 percent effective in preventing serious infant disease caused by RSV during the first 90 days of life.
After six months, the vaccine was still 69 percent effective.
Cases were classified as “severe” when the infected babies were breathing very rapidly, over 70 breaths per minute.
RSV cases were also classified as serious if the patient’s blood oxygen level fell below 93 percent, if they required supplemental high-flow oxygen, if they were admitted to the intensive care unit, or if they lost consciousness.
Severe infections can cause pneumonia and bronchiolitis, an inflammation of the small airways in the lungs.
Worldwide, RSV kills about 100,000 children annually, mostly in poor countries. However, there is no vaccine for the respiratory disease.
dr Eric Simões, a pediatric infectious disease expert at the University of Colorado School of Medicine and Children’s Hospital Colorado, celebrated the maternal vaccine and said it could significantly reduce the number of RSV cases currently in hospitals.
“And if it gets approved by regulators, it’s likely to have a significant impact on disease in the US and around the world,” said Dr. Simões.
Professor Jonathan Ball, professor of molecular virology at the University of Nottingham in the UK, said previous failures to develop a viable RSV vaccine make Pfizer’s news all the more exciting
“Pfizer’s news that its data from early clinical trials suggest good protection against lung infections after vaccination in pregnant mothers (who pass on the immunity to their newborn children) is great news,” said Prof. Ball.
WHAT IS RSV?
Respiratory syncytial virus (RSV) is a very common virus that infects almost all children by the age of two.
In older children and adults, RSV can cause colds and coughs, but in young children it can cause bronchiolitis.
The virus is spread when an infected person coughs or sneezes. It can survive on a surface for up to 24 hours.
Children remain contagious for up to three weeks even after their symptoms have resolved.
RSV is responsible for 450,000 doctor’s visits, 29,000 hospital admissions and 83 child deaths per year in the UK.
In the US, this results in around 58,000 hospitalizations and 100 to 500 deaths in children under the age of five.
Pfizer is expected to be the first company to cross the finish line, but the exact timeline for approval is unclear
Pfizer CEO Albert Bourla told investors on Tuesday that he expects the vaccine could be available in late 2023 or early 2024.
Children’s hospitals across the US are few and far between in the face of a spate of sick children whose immune systems have been shielded from many common pathogens over the past two years.
Two years without RSV, which is widespread, means millions of young children will be exposed to the pathogen for the first time this year.
A combination of social distancing, masking and distance learning put in place to protect people from Covid-19 has effectively stopped infectious viruses like RSV.
After these reduction measures were largely dispensed with, RSV celebrates a brilliant comeback.
This year’s RSV season started about two months earlier than planned. The wave of sick children taking over pediatric wards at major hospitals has forced staff there to adjust who is providing care where.
At the Johns Hopkins Children’s Center in Baltimore, for example, ground nurses are deployed to pediatric patient wards to manage the influx.
Doctors who normally treat adults will begin caring for children in a reversal of early pandemic protocol, when pediatricians were tasked with treating the deluge of adult Covid-19 patients.