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On Monday, the US Food and Drug Administration (FDA) granted approval to Pfizer’s respiratory syncytial virus (RSV) vaccine for administration in women during the middle of their third trimester of pregnancy. This approval aims to safeguard/shield newborns by providing protection against RSV. The vaccine can be administered to women between 32 to 36 weeks into their pregnancy, effectively preventing lower respiratory tract infections and severe ailments in infants up until the age of six months, according to the information provided by Pfizer.
An external panel of experts convened by the FDA had previously embrace the safety and efficacy of Pfizer’s RSV vaccine for pregnant women in their second and third trimesters earlier in May. Although a Pfizer spokesperson did not have insight into the FDA’s rationale for the more specific time frame for vaccine administration, they expressed confidence that the vaccine would positively impact public health and contribute to the reduction of RSV rates. RSV is a prevalent respiratory virus known to cause mild cold-like symptoms, but in certain cases, it can result in severe illness and hospitalization.
The vaccine, marketed as Abrysvo, has previously received approval for utilization in individuals aged 60 and above, serving as a preventive measure against the disease responsible for approximately 160,000 global fatalities annually. Among those affected by the virus, infants are particularly vulnerable to severe complications. In the United States, it’s estimated that 58,000 to 80,000 children below the age of five require hospitalization each year due to RSV infection, as reported by government data.
The US Centers for Disease Control and Prevention (CDC) is yet to provide its endorsement for the vaccine’s usage, which would mark a historic event, as it would be the first maternal RSV vaccine widely accessible in the United States. This authorization is anticipated to follow shortly after the announcement of the approval on Monday. The FDA’s decision was informed by data originating from a late-stage trial that encompassed over 7,000 participants. The trial results demonstrated that the vaccine, when administered to expectant mothers during the latter half of their pregnancy, exhibited an efficacy rate of 82% in thwarting severe infections in infants.
Pfizer reported that the most common side effects observed in pregnant women who received the vaccine included symptoms such as fatigue, headaches, localized pain at the injection site, muscle discomfort, nausea, joint pain, and episodes of diarrhea. These side effects are typical responses to many vaccines and generally indicate the body’s immune system is responding to the vaccine components.
During an advisory committee meeting convened to discuss the vaccine’s safety and efficacy, some experts voiced concerns about a potentially higher occurrence of pre-term births among participants who received the vaccine during the clinical trial, when compared to pregnant women who were part of the placebo group. This observation raised questions about the relationship between the vaccine and its impact on pregnancy outcomes, prompting the need for further investigation and monitoring.
In the field of RSV prevention, Sanofi and their partner AstraZeneca achieved a influential milestone in July when they secured US approval for their antibody therapy named nirsevimab. This innovative therapy is designed to prevent lower respiratory tract diseases among infants and toddlers, particularly those caused by RSV. Additionally, in May, the FDA granted its approval for GSK’s RSV vaccines, specifically aimed at safeguarding older adults from the virus.
This approval not only established a stronger presence for both GSK and Pfizer in the expansive and economically valuable multibillion-dollar RSV prevention market but also showcased the increasing efforts to combat RSV-related illnesses across various age groups. Interestingly, GSK’s vaccine, although approved for older adults, is not being pursued for approval for use in expectant mothers. This could be due to specific considerations or precedence related to the vaccine’s design and target demographic.