Omicron Symptoms Less Severe in Unvaxxed: National Institute of Communicable Diseases

Study comparing thousands of patients shows unvaccinated people infected with Omicron Covid-19 variant are less prone to severe illness, requiring hospital care, or dying.

QUICK FACTS:
  • A South African study by the National Institute of Communicable Diseases (NICD) in the Western Cape region compared about 11,600 patients from the first three Covid-19 waves with about 5,100 from the Omicron-driven wave that began in November, Reuters reports.
  • The study looked at the differences in health outcomes between the vaccinated and unvaccinated, “whether protection against severe disease conferred by prior infection and/or vaccination was maintained.”
  • The study concluded that unvaccinated individuals enjoy less severe symptoms from the Omicron coronavirus variant than vaccinated individuals.
  • “Risk of all outcomes was lower in wave four compared to the Delta-driven wave three (adjusted Hazard Ratio (aHR) [95% confidence interval (CI)] for death 0.27 [0.19; 0.38],” the authors write.
  • But the authors go on to specify that while “Risk reduction was lower when adjusting for vaccination and prior diagnosed infection,” health risk was “reduced further when accounting for unascertained prior infections.”
  • Dr. Mark Sherwood from the Functional Medicine Institute tells American Faith these study results show that “when we have prior infections and have recovered, the risk of negative outcome is improved,” meaning natural immunity from prior infection leads to “at least as good or better health outcomes” when compared to vaccination.
  • These findings raise questions about whether the vaccine is necessary for providing individuals with protection from coronavirus, given that both the vaccinated and unvaccinated enjoy equally less severe symptoms from the Omicron variant.
STUDY METHODS:

“In this cohort study, we included public sector patients aged ≥20 years with a laboratory confirmed COVID-19 diagnosis between 14 November-11 December 2021 (wave four) and equivalent prior wave periods,” the authors explain. “We compared the risk between waves of the following outcomes using Cox regression: death, severe hospitalization or death and any hospitalization or death (all ≤14 days after diagnosis) adjusted for age, sex, comorbidities, geography, vaccination and prior infection.”

BACKGROUND:
  • The South African study authors also noted that Omicron itself is a less dangerous than previous Covid-19 variants, as the Omicron variant’s “intrinsically reduced virulence may account for an approximately 25% reduced risk of severe hospitalization or death compared to Delta.”
  • Omicron globally has tended to cause less severe disease, and proportionally fewer hospital admissions and deaths, than previous variants, Reuters summarizes.