A recent study published by CDC contains concerning findings for the millions of Americans who are considered "immunocompromised," or who have a reduced ability to fight infection or other diseases.
The study finds a majority (53%) of patients who were hospitalized with Covid-19-like illnesses were fully vaccinated with two-dose RNA shots.
According to the study authors, several of whom receive support from vaccine makers, among 20,101 immunocompromised adults hospitalized with Covid-19, 10,564 were fully-vaccinated with Pfizer's or Moderna's shots.
The actual number fully-vaccinated, immune-compromised adults in the hospital may be even higher: the study scientists excluded patients who'd gotten the Johnson and Johnson vaccine, and also excluded vaccinated patients who'd gotten their second dose less than two weeks before hospitalization.
The most common time frame from the second vaccine dose to hospitalization was 89 days, or almost exactly three months.
CDC and the study scientists say they believe the Covid-19 vaccines still qualify as very effective for all groups.
Yet, based on the data showing declining vaccine effectiveness and serious illness from Covid in immune-compromised patients, CDC is now recommending four doses this year for the immunocompromised: the initial two, a booster, and then another booster.
No word yet on how many doses CDC might recommend for these patients next year, since there is no long term data on vaccine effectiveness after boosters.
A large body of scientific evidence continues to indicate that natural immunity after Covid-19 infection is far superior to vaccine immunity. However, most studies do not discuss the subgroup of immune-compromised.
Meantime, the study scientists recommend vaccinated patients who are immunocompromised follow measures and be treated similar to unvaccinated people. This includes masking, "considering non-pharmaceutical interventions and, "if infected [they should] be monitored closely and considered early for proven therapies that can prevent severe outcomes" such as monoclonal antibodies.
The table below shows the number and percentage of vaccinated and unvaccinated immunocompromised adults:
Unvaccinated (Top row, left): 9,537 (47%)
Vaccinated Moderna Middle row, left): 4,337 (22%)
Vaccinated Pfizer (Bottom row, left): 6,227 (31%)