The upcoming RSV season may see a decrease in hospitalisations with the use of efficient vaccines tailored for older individuals and a monoclonal antibody designed for infants.
As the usual cold and flu season approaches this winter, there's promising news regarding preventing a common illness called Respiratory Syncytial Virus (RSV). RSV typically causes mild cold symptoms in most people but can pose serious risks, especially to older individuals and babies. However, two new RSV vaccines are designed for older individuals. A monoclonal antibody intended for children up to age two is expected to become available as early as late summer or early fall.
These advancements in RSV prevention represent a significant shift. Developing an effective RSV vaccine has been challenging for many years, with numerous unsuccessful attempts. However, recent research focused on an essential RSV protein, "RSV fusion (F)," has shown promising results in stimulating the immune system. This progress has led to positive outcomes in clinical trials for two adult RSV vaccines, and there are more potential treatments for RSV in development.
As people age, their immunity weakens, making fending off infections like RSV more challenging. Additionally, the COVID-19 pandemic may have contributed to a loss of immunity against RSV over the past few years, as RSV circulation was minimal during that time. By November 2022, RSV infections were on the rise in children, leading to a tenfold increase in RSV hospitalisations among older adults compared to the usual rate for that time of year. This increase in infections is likely linked to more in-person, maskless interactions.
In June, regulatory authorities approved two vaccines for older individuals, suggesting that those aged 60 and above "may" consider getting vaccinated after discussing it with their healthcare provider. Additionally, this summer, two options received approval for infants and toddlers. A monoclonal antibody known as nirsevimab is now available for all infants up to 8 months old, particularly those born during their first RSV season or entering it. It's also an option for a smaller group of children aged 8 to 19 months at high risk for severe RSV, including those with compromised immune systems.
Furthermore, the authorities approved a vaccine for pregnant women, which provides antibodies that can be passed to the fetus, offering protection against severe RSV for newborns from birth to 6 months of age. The CDC's recommendation for this vaccine is pending; its availability timeline remains uncertain.
These developments in RSV prevention offer hope for both older adults and children, potentially reducing the impact of RSV during the upcoming winter season.
However, RSV can become more severe when it affects the lower respiratory tract, leading to potentially life-threatening complications. Older adults, especially those aged 65 and above, and individuals with pre-existing conditions like asthma, congestive heart failure, and chronic obstructive pulmonary disease (COPD) are at higher risk of developing pneumonia and worsening health issues due to RSV. Annually, this results in significant hospitalisations (ranging from 60,000 to 160,000) among adults aged 65 and older, along with 6,000 to 10,000 RSV-related deaths.
Babies are particularly vulnerable to RSV due to their underdeveloped immune systems and incompletely formed lungs. If the virus reaches the lungs of very young infants, it can lead to respiratory problems, necessitating interventions like supplemental oxygen to aid their breathing.
For children under 5, RSV can result in approximately 2.1 million outpatient visits annually, with 58,000 to 80,000 cases requiring hospitalisation and 100 to 300 RSV-related deaths reported yearly.
Both vaccines designed for older adults employ traditional methods, similar to the approach used for flu shots, and they are distinct from the mRNA technology utilised in Pfizer-BioNTech and Moderna's COVID-19 vaccines. These RSV vaccines operate by introducing an inactivated RSV protein into the body. This protein then binds to host cells, prompting the immune system to recognise the actual RSV virus, should it be encountered, and to prevent severe disease.
Clinical trial data presented indicate that both vaccines performed well. One of them, developed by a pharmaceutical company, received approval based on trials conducted in the United States and internationally. The ongoing study is tracking participants over three RSV seasons. In the initial season, the vaccine demonstrated an overall efficacy of 82.6% against lower respiratory tract disease, with efficacy levels of 77.3% during mid-season and 67.2% over two seasons. In terms of severe disease, it exhibited an efficacy of 94.1% during the first season, 84.6% mid-season, and 78.8% over two seasons.
The second vaccine, developed by another company, exhibited an efficacy rate of nearly 89% against lower respiratory tract disease with at least three symptoms during the first year after vaccination. In the middle of the second season, the efficacy was 78.6%. Lower respiratory tract disease symptoms include new or increased cough, wheezing, phlegm production, shortness of breath, and abnormally rapid breathing (tachypnea).
While the data suggest that a single vaccination could protect for at least two seasons, the frequency of these shots has yet to be determined.
Abrysvo, the same vaccine recommended for older individuals, received approval in August for pregnant women. The vaccine enables mothers-to-be to pass antibodies to their unborn babies, offering protection for up to 6 months after birth. Once CDC approval is finalised, expectant mothers will receive a single injection between 32 and 36 weeks of pregnancy.
Clinical trials conducted for this vaccine in pregnant women demonstrated an efficacy of 81.8% in preventing severe respiratory illness within three months after childbirth and 69.4% effectiveness during the first six months of a baby's life. However, a few advisors raised concerns about a slight increase in preterm births among vaccinated women—5.6% compared to 4.7% in an unvaccinated group (although officials stated this difference was not statistically significant).
Nirsevimab, a medical product co-developed by two pharmaceutical companies, is administered through a single injection into the thigh. A recent study demonstrated a substantial reduction in lower respiratory tract infections triggered by RSV (Respiratory Syncytial Virus), which were severe enough to necessitate medical attention. This reduction amounted to an impressive 76.4%. Additionally, it lowered hospitalisations related to RSV in healthy infants born at or near full term by 76.8%.
Unlike vaccines that stimulate the body to produce antibodies for protection, nirsevimab takes a different approach. It introduces a specific antibody directly into the bloodstream. In the event of an infection with the targeted organism, these antibodies swiftly attach to it, aiding in the clearance of the infection.
This monoclonal antibody effectively reduces the disease's severity and lessens the need for hospitalisation. This development is especially significant given the surge in RSV cases witnessed in the past winter season. The trials revealed no notable differences in adverse effects between the antibody group and those receiving a placebo.
You might not need preventive therapy if you're generally healthy and don't fall into high-risk categories. Most kids naturally build immunity to RSV by the age of 2.
As for older children, teenagers and most adults tend to have strong immunity due to multiple exposures and typically don't experience severe RSV-related respiratory issues. The focus for preventive measures is on those who are at the highest risk. We'll have to wait and see whether vaccines will become available for people in other age groups with chronic underlying health problems, like severe heart or lung conditions.
The group advising on health matters raised some concerns about the data from clinical trials, which led to a change in their initial strong recommendation for the vaccine. Instead of a definite recommendation for everyone eligible, they suggest that people over 60 "may" consider getting an RSV vaccine after a discussion with their healthcare providers. Some may even chat with their pharmacists about it, as Medicare Part D covers RSV vaccines, and pharmacies will often administer them.
One concern was that a few individuals who participated in the trials developed a rare condition called Guillain-Barré syndrome shortly after receiving the vaccine. Guillain-Barré syndrome can cause muscle weakness and, in some cases, paralysis.
Additionally, some participants who received a vaccine called Arexvy experienced atrial fibrillation (an irregular heartbeat that can lead to blood clots in the heart) within 30 days of vaccination. This was also observed in a few individuals who received a placebo.
While there are these potential risks, some experts argue that the benefits of these vaccines outweigh the drawbacks. For example, the protection they offer against severe RSV disease appears to be greater than the small risk of Guillain-Barré in this context. Doctors will closely monitor Guillain-Barré and other potential issues as the RSV vaccines become more widely available.
Another challenge was that most participants in the clinical trials were in their 60s, so there's limited data available for other high-risk groups, like those over 80 years old.
Experts unanimously agree that the benefits of the new vaccines for older adults outweigh any potential drawbacks, particularly in cases where RSV poses a life-threatening risk. These vaccines are recommended for all eligible older adults, especially those with underlying health conditions like heart or lung problems or weakened immune systems.
In addition, it is advised that individuals who are vulnerable to RSV or could potentially transmit it to high-risk individuals should take extra precautions during the fall season. Since RSV is transmitted through contact with contaminated surfaces, these precautions include regular handwashing, refraining from touching the face, avoiding close contact with individuals displaying cold-like symptoms, regularly cleaning frequently touched surfaces like doorknobs and mobile devices, and staying home when feeling unwell. These measures are effective in protecting against RSV.
If you require consultation or assistance regarding RSV, you can conveniently seek help online from Mobi Doctor. Accessible from any device, they provide expert guidance and support to address your concerns.