TEMPLE, Texas – The CDC has released data on the real-world effectiveness of COVID-19 mRNA vaccines in the United States against the Omicron variant. Baylor Scott & White Health – Temple also contributed to this data.

The findings are from a multi-site analysis from ten states of 222,772 emergency department (ED) and urgent care (UC) encounters and 87,904 hospitalizations among adults with COVID-19–like illness August 26, 2021–January 5, 2022, which includes the time period before and after the Omicron variant became the predominant strain.

  • A third dose was highly effective during both the Delta- and Omicron-predominant periods at preventing COVID-19-associated ED and UC encounters (94 percent and 82 percent, respectively) and at preventing COVID-19-associated hospitalizations (94 percent and 90 percent, respectively).

·         During both periods, vaccine effectiveness was significantly lower among patients who received their second mRNA COVID-19 vaccine dose more than 180 days before the medical encounters compared with those vaccinated more recently – showing waning of vaccine protection over time.

·         Estimates of mRNA vaccine effectiveness against laboratory-confirmed COVID-19 were lower for ED/UC visits among those recently vaccinated less than 180 days ago during the Omicron-predominant period compared with vaccine effectiveness during the Delta-predominant period – suggesting more immune evasion by the Omicron variant.

  • These findings underscore the importance of receiving a third dose of mRNA COVID-19 vaccine to prevent both moderately severe and severe COVID-19, especially while the Omicron variant is the predominant circulating variant and when the effectiveness of two doses of mRNA vaccines has significantly waned over time against this variant.
  • All unvaccinated people should get vaccinated as soon as possible.
  • All adults who have received mRNA vaccines during their primary COVID-19 vaccination series should receive a third dose when eligible, and eligible people should stay up to date with COVID-19 vaccinations – including immunocompromised people who are eligible for a booster dose five months after their third primary dose.

“We are honored that our Texas-based team was able to again contribute to the global effort to understand and prevent COVID-19 illness,” said Alejandro Arroliga, MD, chief medical officer, Baylor Scott & White Health. “The data out today, some of which came from our hospital in Temple, shows that a third dose was highly effective at preventing hospitalizations related to COVID-19. A 90 percent effectiveness rate is further proof that the vaccines are working to prevent severe illness and hospitalization, which is what they were intended to do.”

Source: Baylor Scott & White Health