Studies are now in progress to evaluate the long-term effects of COVID infection in the U.S.  According to a report in the Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report, the national prevalence of long-COVID is 6.4 percent of all adults ranging from 1.9 percent in the U.S. Virgin Islands to 10.6 percent in West Virginia.  Long-COVID at 30 days was 43 percent lower in respondents that were fully vaccinated before infection.  Symptoms of long-COVID were 58 percent less evident in vaccinated individuals at 90 days after infection.  This is considered noteworthy as 17.5 percent of respondents among 4,605 surveyed in the Michigan COVID-19 recovery surveillance study reported symptoms 90 days after infection.

Individuals affected by long-COVID demonstrated high levels of interferon gamma (IFN- γ) for up to 31 months after infection.  This protein usually declines shortly after recovery from COVID.

MRI scans of patients with long-COVID and neural abnormalities showed dysfunction of the blood-brain barrier.  These changes were absent in patients recovering from COVID without self-reported symptoms including “brain fog”.

It is well established that immunization against COVID protects against the consequences of acute infection.  It now is apparent that immunization protects against the adverse effects extending beyond 90-days post infection.