Of . – 07/11/2022 09:17 (act 07/11/2022 13:04)
A new vaccine for pregnant women aims to protect babies from the RSV virus. ©APA/DPA/FREDRIK VON ERICHSEN (subject)
Respiratory syncytial virus (RSV) is a threat to the lives of infants and the elderly. Now, a new Pfizer vaccination for pregnant women should reliably protect newborns.
A new vaccine given to pregnant women could protect babies from the syncytial virus. In an efficacy study, vaccinating pregnant women with a new vaccine (Pfizer) reliably protected newborns. The British pharmaceutical company GlaxoSmithKline has already approved a vaccine for the elderly.
Pfizer’s vaccination of pregnant women protects babies from the virus
“The effectiveness of the vaccine in preventing severe RSV disease requiring medical intervention in newborns in the first three months of life was 81.8 percent. In the first six months of life it was 69.4 percent. RSVpreF – Candidate was well tolerated. There were no safety concerns for the vaccinees or their babies,” Pfizer said a few days ago on the topic of vaccinating pregnant women.
Vaccination concept: pregnant women transmit antibodies to babies
The concept of vaccination is remarkable: immunization of pregnant women aims to provide protection against viruses, which can lead to severe respiratory diseases, by transferring the resulting antibodies from pregnant women to the unborn child. This concept was tested in the now completed approval study. In this Matisse study (MATernal Immunization Study for Safety and Efficacy), approximately 7,400 pregnant women in 18 countries were randomly vaccinated with a single 120 microgram dose of the vaccine or placebo. This happened towards the end of the second or third trimester of pregnancy. “The study started in June 2020 and therefore covered several waves of disease,” wrote Deutsches Ärzteblatt. RSV disease waves are typical of the cooler seasons, often as early as early autumn.
Development of RSV vaccines with tragic incidents
The development of such RSV vaccines was preceded by many years of intensive research with, in one case, tragic incidents. Molecular biology has made the crucial advance in the search for suitable antigens. Efficacy and side effects in pregnant women and their children depend on the form of the proteins used. In the search for a protein that could serve as an antigen for vaccines against RSV, the RSV fusion protein (F) was identified a few years ago, which mediates the fusion of the viral envelope with the cell membrane during infection. In 2000, electron microscopy studies revealed an interesting detail: RSV-F exists in two forms, a pre-fusion structure and a post-fusion structure.
“The protein changes and refolds. When that happens, the virus and the cell membrane fuse,” Jason McLellan, a structural biologist at the University of Austin, Texas, told Science earlier this year. Spanish scientists have finally proved that the RSV pre-fusion protein is the most suitable. Pfizer’s vaccine candidate contains RSV pre-fusion proteins from two variants of the RS virus.
23 children seriously ill in 1965 despite vaccination
Catastrophic events with a vaccine candidate occurred in 1965. At that time, 31 infants received a heat-inactivated and formalin-inactivated inactivated vaccine as part of a US National Institutes of Health (NIH) study. But 23 of the children aged between two and seven months were still infected and 18 had to go to the hospital. Two of the children died. There was only one case of infection in the control group. Finally, it was found that vaccination with the then-killed whole-virus vaccine – the new vaccines contain only individual proteins – apparently made children more sensitive to RS viruses. Heat and formalin inactivation resulted in F protein remodeling in post-fusion morphology. There was no immune protection and, at the same time, vaccination led to a particularly severe course of the disease.
Problems with new vaccines solved by pre-fusion proteins
Such problems are now eliminated with the use of pre-fusion proteins in the new vaccines. Pfizer now intends to apply to the US Food and Drug Administration (FDA) for approval of its vaccine. At the same time, studies are being carried out with the vaccine in the elderly. British pharmaceutical company GlaxoSmithKline (GSK) has also developed a vaccine for this age group that has proven itself in clinical studies and is currently being examined by the European Medicines Agency (EMA) for approval. It is clear that the vaccine must provide direct protection for adults and babies through “bypassing” their mothers.
RSV virus is especially dangerous for children in their first year of life
“Annual RSV epidemics are particularly dangerous for children in the first year of life. Children suffer from what is called bronchiolitis, which can jeopardize an adequate supply of oxygen. In the winter months there is therefore an increase in hospitalizations and care intensive treatments,” he said in the German medical journal.
Premature babies and newborns are particularly at risk. According to the German Robert Koch Institute (RKI), about five percent of congenital heart defects are fatal.