Both new RSV vaccines are highly effective (over 80%) at preventing RSV disease.
As we’ve recently covered, RSV can be a nasty illness for older adults, landing hundreds of thousands in the hospital each year and causing around ten thousand deaths annually in the US. The good news is that there are two new RSV vaccines approved for adults ages 60 years and older – GSK (branded as Arexvy) and Pfizer (branded as Abryvso). Both are single-dose vaccines that introduce an inactivated protein from the virus into the body, causing the immune system to produce RSV antibodies. GSK’s vaccine includes an adjuvant (the same adjuvant used in the Shingrix vaccine), which is an ingredient that increases the immune response to a vaccination. Pfizer’s vaccine does not contain an adjuvant.
The GSK trial enrolled almost 25,000 people 60 and over, half of whom were randomized to receive a single dose of the RSV vaccine (treatment group) and the other half a placebo shot (control group). Over the next 7 months of follow-up, the vaccine group had a rate of PCR-confirmed RSV that was 82.6% lower than the control group (that’s how we calculate efficacy). Protection was even better against severe disease, with 94.1% efficacy. There were no differences in efficacy by age or health status.
Source: New England Journal of Medicine
The Pfizer trial enrolled over 36,000 people aged 60 and over from seven countries. The efficacy of their vaccine was 88.9% against laboratory confirmed RSV in the first season, and 78.6% in the second RSV season. Participants did not get a second shot in that second season, so this tells us the protection lasts at least two seasons.
Overall, both vaccines showed excellent protection against RSV disease, and that this protection likely lasts more than one season (more follow-up will hopefully tell us how long).
Current CDC guidelines recommend that adults aged ≥60 years may receive a single dose of an RSV vaccine after having a conversation with their clinician. RSV cases are on the rise, so now is a great time to go get your shot, especially before the holidays. You can get an RSV vaccine at the same time as other vaccines, like the Flu or Shingles vaccine.
Stay safe, stay well!
Those Nerdy Girls
