On Monday, the Food and Drug Administration granted approval to a vaccine designed for administration to pregnant individuals. This vaccine aims to safeguard infants from RSV (respiratory syncytial virus) during their initial six months of life.
In a groundbreaking development, the Food and Drug Administration (FDA) approved a vaccine. This vaccine is designed to safeguard infants from the respiratory syncytial virus (RSV).”
Pfizer, a pharmaceutical giant known for its pioneering work in vaccine development, has produced a single-dose shot named Abrysvo. This vaccine triggers the production of protective antibodies transferred from the mother to the infant through the placenta. It marks a significant milestone. This is the first vaccine to protect against RSV, a virus notorious for causing severe lower respiratory illnesses in infants.
However, it’s important to note that just last month, the FDA approved an injectable RSV drug for infants, delivering a direct dose of antibodies into the bloodstream.
Before Abrysvo can be made widely available to the public, an advisory committee to the Centers for Disease Control and Prevention (CDC) must determine the target demographic for vaccination.
Following this, Dr. Mandy Cohen, the Director of the CDC, will formally endorse the vaccine. Pfizer anticipates that the CDC advisory committee will convene by early October. The vaccine is expected to become accessible shortly after its official endorsement.
The Abrysvo Vaccine – Targeting Pregnant People at 32 to 36 Weeks Gestation
The newly approved Abrysvo vaccine is intended explicitly for pregnant individuals at 32 to 36 weeks gestation. Notably, this vaccine received approval in late May for individuals aged 60 and older and is already available at select Walgreens locations.
RSV infections are typically mild, with most children contracting the virus by age 2. However, in severe cases, RSV infections can lead to pneumonia or bronchiolitis, which can inflame the airways and cause blockages due to mucus buildup. Vulnerable populations include older adults and babies, with RSV responsible for up to 300 deaths annually among those under the age of 5 in the United States and up to 160,000 hospitalizations among individuals aged 65 and above.
The previous RSV season, they witnessed a dramatic surge in severe illnesses, leading to overwhelmed children’s hospitals. A recent study published this month revealed that most babies admitted to the intensive care unit with RSV in late 2022 were previously healthy and born full-term.
Abrysvo’s Clinical Trial – Promising Protection Against RSV
Tamara Zangrilli, an operations coordinator at Children’s Hospital Colorado, was among the first individuals to receive the Abrysvo vaccine while pregnant. Her decision was not taken lightly, as she and her husband deliberated extensively before opting for the experimental vaccine.
“We, really, really discussed it. Zangrilli shared, “My husband and I deliberated for three days, contemplating whether we should proceed.”
Ultimately, her concern for her baby’s well-being led her to participate in Pfizer’s clinical trial in 2021.
In the clinical trial involving nearly 7,400 participants, Abrysvo reduced the risk of severe RSV-related illnesses in infants by 82% within approximately three months after birth. By the six-month mark, the vaccine’s efficacy was around 69%.
Dr. Bill Gruber, Pfizer’s senior vice president of clinical research and development, stated, “If we introduce it widely, it will stop some children from requiring hospitalization or ventilators this winter.”
Among pregnant women who received the shot, the most common side effects reported were fatigue, headache, injection site pain, muscle pain, nausea, joint pain, and diarrhea.
Addressing Concerns and Looking to the Future
In May, a committee of experts appointed by the FDA meticulously examined data concerning the vaccine. The group generally praised its effectiveness. However, they raised some concerns about the duration of protection and the potential risk of preterm birth. Throughout the trial, observers noted that individuals who received the vaccine (5.7%) had a slightly higher rate of giving birth before reaching 37 weeks of gestation. This is in comparison to those who received a placebo (4.7%).
Although these rates were not statistically significant, the vaccine’s prescribing label warns against administering Abrysvo before 32 weeks gestation. This caution is due to this numerical imbalance. According to the CDC, it’s important to note that both observed rates were lower than the rate of preterm births in the general population. This rate typically hovers around 10%. Pfizer has committed to ongoing monitoring of the risk of preterm birth among vaccine recipients.
Dr. Gruber reassures the public: “There’s a long track record of safety for administering vaccines to pregnant women.” This applies to diseases like pertussis, influenza, and tetanus.
Two Options for Infant Protection: Abrysvo and Beyfortus
Unlike previous RSV seasons, expectant parents and those with young infants now have two options to protect their children.
The CDC recommends the antibody injection, Beyfortus, for babies up to 8 months old. This recommendation applies to those born during or entering their first RSV season, which typically commences around October. They also recommend it for infants aged 8 to 19 months. This recommendation is for those who face an increased risk of severe disease in their second season.
While Abrysvo may offer a broader antibody response that resembles the body’s natural defense against viruses, we currently lack direct data comparing the two vaccines.
Health authorities have not yet issued recommendations regarding expectant mothers. They haven’t clarified whether those planning to vaccinate their infants with Beyfortus should also consider receiving the Abrysvo vaccine. This issue may be a subject of discussion for the CDC’s advisory committee.
Zangrilli, who participated in the Abrysvo clinical trial, reports that her 18-month-old son, Harrison, has not tested positive for RSV. She remains open to receiving the vaccine again if health authorities recommend it for future pregnancies.
FDA’s approval of Pfizer’s Abrysvo vaccine offers hope for protecting infants from severe RSV-related illnesses. While some have raised concerns about preterm births, we will continue refining our understanding of the safety and efficacy of this groundbreaking vaccine. This will be achieved through ongoing monitoring and research.
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