RSV
Olivia C. Welter, PharmD
In the summer of 2023, after many years of research and clinical trials, FDA approved several agents to prevent RSV. Since most of these products have been commercially available for over a year now, researchers have collected real-world data to prove the effectiveness of RSV vaccines and the monoclonal antibody nirsevimab, which is used to prevent severe RSV disease in infants and young children.
Clinicians and patients now have more experience and knowledge to guide decision making. Here’s what is known from the research so far.
Older adults
Current data show that the available RSV vaccines, Arexvy and Abrysvo, are generally safe and effective in older adults.
Clinical trials for RSV vaccines in older adults identified Guillain-Barré syndrome as a potential safety concern. CDC’s Morbidity and Mortality Weekly Report (MMWR) from May 30, 2024, stated that patients reported the rare autoimmune condition at a rate of 4.4 and 1.8 reports per million administered doses of Abrysvo and Arexvy, respectively. CDC and FDA use these types of reports to continue assessing the benefits of RSV vaccination compared to risks.
Findings from an article published online on August 23, 2024, in the Journal of Infectious Diseases, which assessed whether place of residence is a risk factor for RSV hospitalization, revealed a higher incidence of RSV hospitalization for older adults living in long-term care facilities than those living in other housing. These findings affirm that residence in a long-term care facility is a major risk factor for RSV infection.
In a research letter published online on September 4, 2024, in JAMA, the authors wrote that RSV vaccination was associated with a reduced likelihood of hospitalization in patients aged 60 years and older compared to patients who had not received an RSV vaccine. Surie and colleagues noted that their study expanded on prelicensure trial data in two important ways: providing evidence of vaccine protection against RSV-associated hospitalization and demonstrating protection in a population that more closely represents those at high risk of severe RSV disease.
Research published online on October 19, 2024, in The Lancet concluded that RSV vaccines were 80% effective in preventing hospitalization, ICU admission, and death among adults aged 60 and older. The study also showed consistent protection throughout the entire RSV season.
Infants and patients who are pregnant
According to CDC, RSV is the leading cause of hospitalization for infants. CDC’s MMWR published on March 7, 2024, highlighted a CDC study that showed that nirsevimab is 90% effective in preventing infants from being hospitalized with RSV.
On September 26, 2024, a report in MMWR stated that provider recommendation for receiving an RSV vaccine was associated with higher rates of RSV immunization in patients who are pregnant. The report also revealed that 38% of respondents asked to receive an RSV vaccine during pregnancy, while 28% preferred nirsevimab administration for their infant. Thirteen percent of respondents indicated that they would not use any methods to prevent their infant from RSV infection.
Making recommendations
As research has revealed, providers play a key role in increasing uptake for RSV prevention agents.
“There are millions of adults in each state who don’t even realize they are vulnerable to serious infections that vaccines can prevent,” said John D. Grabenstein, RPh, president of Vaccine Dynamics. “That’s especially true for RSV vaccines because they are relatively new.”
Grabenstein said pharmacists can increase immunization rates.
Providers must understand risk factors for severe RSV disease to make appropriate recommendations. For older adults, clinicians should identify patients who are aged 75 and older, have chronic heart or lung disease, have other underlying medical conditions, such as diabetes or obesity, or live in a long-term care facility.
For infants, providers can screen for risk factors, including chronic lung disease, prematurity, a weakened immune system, severe cystic fibrosis, and American Indian or Alaska Native heritage. Providers should explain that receiving an RSV vaccine or nirsevimab can prevent hospitalization in patients with these risk factors.
Future of RSV prevention
Available data showed low uptake of RSV vaccines in the first year following their approval.
According to CDC, only 20% to 25% of adults aged 60 and older received an RSV vaccine. CDC also reported that RSV vaccination coverage among eligible patients who were pregnant was approximately 33%.
“We will see slowly increased uptake year after year, as more people realize that hospitalization could have been prevented,” said Grabenstein.
According to Jean-Venable “Kelly” R. Goode, PharmD, and APhA ACIP liaison, ACIP is considering adding recommendations for RSV vaccines in younger populations following FDA approval of Abrysvo for adults aged 18 to 49 years at increased risk for the disease and Arexvy in adults aged 50 to 59 years at increased risk for lower respiratory tract disease caused by RSV.
She added that she believes there is a knowledge gap related to safety of RSV vaccines and nirsevimab.
“RSV vaccine safety is continuing to be monitored through multiple mechanisms by the CDC. This information is always important,” said Goode. She encourages pharmacists to promote the V-safe program, which collects vaccine safety data, to patients.
Goode also noted that potential for revaccination, appropriate time frame for multiple doses, and appropriate number of doses for optimal effectiveness require additional research.
“The RSV vaccine will continue to be recommended by ACIP, and when more data become available, revaccination will be part of the future of RSV vaccines,” said Goode. ■