Vials of Pfizer’s new respiratory syncytial virus (RSV) vaccine Abrysvo in production.Pfizer/Reuters
Health Canada has approved the first antenatal vaccine against respiratory syncytial virus. This is a milestone that will reduce the damage that RSV causes to infants and Canadian children’s hospitals each winter.
New shots decided by regulators approved Thursday is designed to be given to pregnant women late in pregnancy so they can pass antibodies against RSV to their newborn.
It is important to protect infants because respiratory syncytial virus is a common pathogen that usually causes only a mild cold and can cause complications such as bronchiolitis and pneumonia in infants. A virus is the main cause Rate of hospitalization of infants under 1 year of age in Canada.
Health Canada has also approved vaccination for adults aged 60 and older, another demographic group more susceptible to severe disease caused by RSV. The new shot, called Abrysvo, is the second shot approved to prevent serious RSV disease in older adults.
Jesse Papenberg, a pediatric infectious disease specialist and medical microbiologist at the Montreal Children’s Hospital, said that once a maternal vaccine becomes widely available alongside nilcevimab, another new vaccine that protects infants from infection, RSV predicted there would be a “clear difference” in the pressure on children’s hospitals. R.S.V.
Nilsevimab, approved by Health Canada last April, is a monoclonal antibody injection given once a season to newborn infants. Both Abrisvo and Nilsevimab provide passive immunity to RSV in the form of antibodies that babies don’t make on their own. Usually, if a pregnant mother receives Abrisvo, her baby will not need nirsevimab.
“RSV is a huge burden, so if we could reduce that burden by 60 to 80 percent, that would be huge for pediatric hospitals,” Dr. Papenburg said. “That’s not an exaggeration – [RSV] It is the leading cause of hospitalization in children under 1 year of age and is responsible for a significant number of emergency department visits. ”
of clinical trial With this, Health Canada and other international regulatory authorities have approved Abrysvo and found that Abrysvo is 81% effective in preventing severe lower respiratory tract illness caused by RSV that requires medical attention in infants under 3 months of age. It has been found. The effect diminished as the baby grew older.
The trial, in which participants were given the real vaccine or a placebo between 24 and 36 weeks of pregnancy, found a possible association between the vaccine and an increased risk of preterm birth, although the finding was not statistically significant. was detected. To reduce possible risks, Health Canada followed the lead of the U.S. Food and Drug Administration and approved the shot between 32 and 36 weeks of pregnancy, when babies are nearing term.
Dr. Papenburg said the challenge now is to provide Canada with sufficient supplies of both maternal vaccines and monoclonal antibodies at reasonable prices, and to persuade parents to use them.
Despite being approved last spring, nilsevimab is not widely available in Canada due to supply shortages, in part due to high demand in the United States. The U.S. Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices Recommendation This injection is given to all infants under 8 months of age entering their first RSV season and to high-risk infants entering their second RSV season.
The same US panel recommended that the new maternal RSV vaccine be given to all pregnant women between 32 and 36 weeks of pregnancy. Canada’s National Advisory Committee on Immunization has not yet issued any recommendations on new ways to protect infants from her RSV.
Pfizer, the maker of Abrisvo, said Thursday it is still determining when Canadians will have access to the new vaccine. Andrea Muller, head of primary care portfolio at Pfizer Canada, said in an email that the company is “committed to getting this medicine to Canadians as soon as possible, possibly as early as late spring.” Ta.
He declined to say how Pfizer plans to price its vaccine in Canada, but said the company intends to work with policymakers to make the vaccine more accessible.
Darin El Shaar, a maternal-fetal medicine specialist at the Ottawa Hospital, said the future uptake of prenatal respiratory syncytial virus vaccination will be high because it is intended to protect pregnant women’s babies. I think it’s possible. (Dr. El Char has received compensation from Pfizer for serving on an advisory board for Abrisbo.)
“Mothers-to-be will choose something that will protect their baby, but not something that will protect them,” Dr. El Char said. “What you have to see is [pertussis] Vaccine coverage in Canada. It’s much more expensive than a flu shot.
In the most recent year, 2021, survey data According to data available from Statistics Canada and the Public Health Agency of Canada, 65 per cent of pregnant women are vaccinated to protect their babies from whooping cough.
In contrast, only 53 percent of mothers-to-be in 2021 received a flu shot. Although it is recommended as a means of protecting women who are at high risk of influenza complications during pregnancy, the vaccination provides some protection for the baby. good.
What questions, thoughts, or concerns do you have about this year’s respiratory virus season?
The Globe and Mail’s weekday news podcast, The Decibel, wants to help answer your questions about RSV, COVID-19 and the flu this winter.