Close-up image of vaccination being given in upper arm of older individual
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Real-world experience now corroborates the results of clinical trials of COVID-19 vaccines, according to a multistate analysis conducted by the Centers for Disease Control and Prevention in collaboration with six U.S. healthcare systems plus the Regenstrief Institute.

The study looked at hospitalization and intensive care unit data for patients older than 50 from a total of 187 hospitals, in addition to data from emergency departments and urgent care clinics. The data, which covered 45,000 medical encounters, showed that 2-dose COVID-19 vaccinations provide high levels of protection for populations disproportionately affected by the virus, including older adults and minorities.

In particular, the analysis found that two doses of either the Moderna or Pfizer vaccines was 89% effective at preventing COVID-19 hospitalizations, 91% effective at preventing COVID-19 emergency department or urgent care visits, and 90% effective at preventing COVID-19 intensive care unit admission.

The effectiveness was significantly lower in individuals who received only the first dose of the two shot-vaccination, however.

“This study confirms that these vaccines are highly effective,” said lead author Mark Thompson, PhD, a member of the CDC COVID-19 Response Team. “They offer significant protections for people older than 85, people with chronic medical conditions, as well as Black and Hispanic adults. All are groups who have been hit particularly hard by this disease.”

The study was also one of the first to look at the effectiveness of the single-dose Johnson and Johnson vaccine, which was found to be 73% effective against emergency department and urgent care visits, and 68% against hospitalizations.

Full findings can be found in the New England Journal of Medicine.