Covid-19 mRNA vaccines work very well in real life. But as more data are analyzed it appears that certain groups of people such as seniors (65+) do not benefit as much from the vaccine.
We have been tracking the vaccine’s real-life efficacy through Florida’s Seniors First program to vaccinate everyone over 65 years old first. As of April 19th, 3.6M seniors or 80% have been vaccinated with 2.9M (64%) completing the two-dose regime. The pace of senior vaccinations has slowed recently and this may be linked to the plateau and now rise in relative infection for seniors (see figure below).
There are several possible explanations for this observed phenomenon:
1. Vaccine hesitancy expressed by 27% of Americans in recent polling, Note that 80% of Florida seniors have already gotten their shot so polling answers may be more political posturing rather than reality. Nevertheless, at some point before 100%, we will reach seniors who resist the vaccine, and improvement in relative infectious of seniors will end.
2. Weaker vaccine protection for seniors. While mRNA vaccines are near 95% effective and people who are fully vaccinated have only a 5% chance of getting COVID-19 on average, people over 65 are less protected and may have as high as 39% chance of getting infected – near 8 times higher than average. JnJ vaccine provides less protection for everyone. Seniors typically have more comorbidities such as weakened immune systems and this may be one reason for their weaker protection. As the rest of the state and country get vaccinated relative infection rates for seniors could increase more.
3. Premature relaxation of precautions after vaccination, especially in the 65-74 yrs old that are mobile. Those vaccinated who drop masking and social distancing (which combined may be 90% effective) could reduce their overall protection against the virus.
4. Vaccine effectiveness is believed to be 90% after 6-mo in general for mRNA vaccines, but this may not be true for seniors who may have shorter protection. Seniors may require more frequent booster shots.
5. New and more contagious variants spreading now though Florida are not believed to escape mRNA vaccine clutches, but current vaccines may provide less protection against the new variants and may need to be re-tuned.
All of these factors suggest that it would be prudent for seniors to continue to follow good public health advise for masking, social distancing, and travel. International travel to 80% of the world is discouraged by the US state department especially with the pandemic raging to record highs globally led by surges in India, Brazil, Turkey, and other hotspots around the world.