This Monday, the Food and Drug Administration (FDA) gave its approval to Pfizer's vaccine against the respiratory syncytial virus, also known as RSV. The vaccination is intended for persons aged 60 and older.
This will be the second RSV vaccine that is commercially accessible in the United States after a formulation developed by the pharmaceutical giant GSK was given the green light a month ago. Approval from the Centers for Disease Control and Prevention (CDC) is still required.
Abrysvo, a vaccine developed by Pfizer, is intended to protect against diseases of the lower respiratory tract that are caused by RSV.1 In most people, the illness manifests as mild symptoms similar to those of the common cold. However, in high-risk groups such as small children and elderly adults, the illness can be severe and even fatal.
Last winter, record-high cases of respiratory illnesses were caused by RSV, influenza, and COVID-19, causing some public health professionals to refer to the outbreak as a "tripledemic" of respiratory sickness. The disease took an especially harsh toll on children; infants younger than one-year-old were hospitalized at a rate that was more than ten times higher than it was at the same stage in 2019.2
However, RSV can also cause significant illness and even death in people who are above the age of 65.3 According to estimates provided by the CDC, RSV is to blame for at least 177,000 hospitalizations and 14,000 fatalities that occur annually among adults in the United States.4
"We've learned that RSV often is serious as influenza in causing serious respiratory disease in older person year in and year out," William Schaffner, MD, the medical director of the National Foundation for Infectious Diseases and a professor of infectious diseases at the Vanderbilt University School of Medicine, said in an interview with Verywell. Dr. Schaffner is also an infectious diseases professor at the Vanderbilt University School of Medicine. "Therefore, the availability of some vaccines for the prevention of RSV in older persons is truly a very significant advance,"
A single dosage of Pfizer's vaccine was shown to be approximately 67% effective in avoiding RSV cases with at least two symptoms, and 86% effective in preventing cases with at least three symptoms, according to the findings of phase 3 clinical trial that included more than 34,000 people aged 60 and older.5
The effectiveness of the vaccine in a single dosage is due to its ability to inhibit the action of a crucial protein that facilitates the virus's invasion of human cells.
RSV-related symptoms
The following are some of the common symptoms of RSV:
- Runny nose
- Reduced hunger and appetite
- Coughing
- Sneezing
- Fever
- Wheezing
The efficiency of the vaccination looks to be on par with that of GSK's RSV vaccine, which in clinical testing was approximately 83 percent effective at preventing diseases of the lower respiratory tract.7
According to statements made by both businesses, their respective vaccinations will be made accessible well in advance of the next RSV season, which begins in the early fall. A group of CDC experts will get together the following month for a conference to examine the RSV vaccine recommendations that should be given to health professionals.
Pain at the injection site, muscle stiffness, and exhaustion are mentioned as the most common side effects associated with both vaccination candidates, according to the study that has been done so far.
Panelists reviewed an elevated risk of autoimmune dysfunction that may be related to the vaccine during a meeting held by the FDA on March 1. There was one instance of Guillain-Barré syndrome and one case of a rare form of that disease called Miller Fisher syndrome in Pfizer's clinical trial. Both of these syndromes are extremely rare. These potentially life-threatening adverse effects occurred relatively seldom, with only one case for every 9,000 patients. On the other hand, this is a significantly higher rate than the average of one to two people per 100,000 who are diagnosed with Guillain-Barré syndrome each year.
According to Schaffner, who was the chair of the advisory group, the committee had concluded that these statistics might be a "statistical fluke." The vaccine's acceptance was recommended by the panel, which had a vote count of 7-4. Schaffner stated that he anticipates the Centers for Disease Control and Prevention (CDC) will concur with the Food and Drug Administration (FDA) that the vaccine is safe for older persons.
During the most recent RSV season, infants and toddlers were affected the most severely. A maternal vaccination developed by Pfizer and a monoclonal antibody designed for infants is both part of the RSV protection for children that are currently being evaluated by regulatory agencies.
Additionally, several RSV vaccinations designed for older adults are currently in the development stage. Within the next two months, according to Moderna's statement, the company anticipates submitting results on its mRNA vaccine for RSV in seniors. In addition, Bavarian Nordic stated that it plans to announce the findings of a phase 3 study of its vaccine this year.
Schaffner stated that vaccination is what truly protects against disease, not the vaccines themselves. "Now that we have figured out how to get these RSV vaccines out of the refrigerator and into the hands of older persons regularly, we need to figure out how to do it again." Going forward, that is going to be a challenge."