Q: COVID-19 rates are coming down. That's good news, right?
A: COVID-19 cases and hospitalizations overall have been decreasing. The seven-day moving average in Hamilton County last week was 10 new cases per day, compared to a seven-day average of 422 per day earlier this year. These reassuring trends are likely due to a large number of individuals who are now protected either because of having had a COVID-19 infection or the COVID-19 vaccine. The decline in cases also is likely due to seasonal patterns of viral infections, which are usually less frequent during the summer months.
Despite this reassuring decrease in cases, however, concerns remain about the potential of an increase in viral activity again in the fall, particularly given the low vaccination rates and the presence of more transmissible and potentially more severe variants. The B.617.2 (delta) variant was recently changed from a variant of interest to a variant of concern. Variants of concern are those that have evidence of increased transmissibility and more severe disease. Studies from England suggest people infected with the delta variant are about twice as likely to end up in the hospital, and available treatments may be less effective.
The delta variant is 60% more transmissible than the alpha variant (B.1.1.7), which was first identified in the United Kingdom and is the current dominant strain in the United States. First identified in India, the delta variant has now been found in almost every state in the U.S. A recent study looking at samples collected across the U.S. as of April of this year showed the delta virus rapidly replacing the previous dominant alpha virus. The delta variant currently accounts for about 21% of cases sampled and is expected to become the dominant variant.
The observed increase in the delta variant, however, is not the same in all parts of the country. Increases are greater in areas of the country with low vaccination rates. The highest increase is mostly in the Midwest and Southeast regions of the country. The Centers for Disease Control and Prevention's national genomic surveillance system identified the delta variant in 1.5% of samples collected in Tennessee over a four-week period. As of earlier this month, 27 cases of the delta variant were reported in Tennessee.
Current vaccines offer good protection against variants, including the delta variant. The risk now is mostly for those who have not been vaccinated. In fact, most hospitalizations and deaths are now occurring mostly in unvaccinated individuals. Fully vaccinated individuals have a much lower risk of infection.
The best way to prevent infection is to get vaccinated. Eligible individuals not yet vaccinated are encouraged to do so. The more people are vaccinated, the less likely we will have another serious surge in the fall.
For information on vaccine location sites, call 423-209-8383 or visit health.hamiltontn.org.
Fernando Urrego, M.D., is the interim health officer at the Hamilton County Health Department and a member of the Chattanooga- Hamilton County Medical Society.
Contributed Photo / Dr. Fernando Urrego