The good news is that there are now 3 approved COVID-19 vaccines in the USA with more than enough doses to allow all American adults to be vaccine eligible by May 1st. Two of the vaccines, Moderna and Pfizer-BioNTech, have already proven to be very effective in the field. These are two-dose vaccines that can take 6 weeks to achieve full protection. One way to track real-life efficacy is through Florida’s Seniors First program to vaccinate everyone over 65 first. As of March 13th, 2.93M seniors or 65% have been vaccinated with 1.75M (39%) completing the two-dose regime. If the vaccine is effective, the number of daily cases, hospitalizations, and deaths should all come down.
The graph below tracks the relative susceptibility of Floridians by age to SARS-CoV-2 infections. Seniors have always been more careful to mask-up and social distance since the first COVID-19 cases appeared in Florida and killed hundreds of seniors last spring. Moreover, the oldest seniors (85+) have been the least mobile and thus least likely to spread the virus. After rising slightly post year-end holiday gatherings that increased community transmission, relative infection rate (i.e. number of cases per capital for the age group divided by the number of cases per capita for the whole population) has steadily declined over the last 4 weeks from mid-February to mid-March for all seniors. We are forecasting that these relative infection rates will continue to decline steadily for another 4 weeks as the number of fully vaccinated seniors approach 3.2M or 70% of the group population. After that, we believe that the rate of decline will slow and will run up against a stubborn core group of people refusing vaccines (estimated to be 27%).
This steady decline in senior susceptibility to COVID-19 will positively impact the overall case fatality rate (CFR = deaths/cases). CFR has decreased from 2.5% in the first wave to 2.0% for the second wave to 1.5% for the third wave in FL. We believe this will decrease below 1% soon as the median age of new cases falls further below the current value of 37 years old.
This however does not mean that the virus will no longer be a threat. The bad news is that the relative susceptibility of kids to SARS-CoV-2 has been increasing since school reopened in FL last year. The trend appears to have worsened with the spread of the new and more contagious variants this year. It could be several months before any vaccine is approved for kids under 16. In the meantime, schools can reopen but it is important that teachers and staff get vaccinated, facilities get upgraded (e.g. ventilation), and masking and social distancing be enforced to mitigate the spread of the disease in schools.