Three doses of mRNA Covid-19 vaccines, either Pfizer-BioNTech or Moderna, are effective in protecting against emergency department visits (ED) and hospitalisations associated with Omicron and Delta variations of the virus, claims a new study.
The study, from the US Centers for Disease Control and Prevention (CDC), found that boosters of mRNA Covid vaccines are 82 per cent effective in protecting against Omicron variant-associated ED visits.
It also found that booster shots are 90 per cent effective in protecting against Omicron variant-related hospitalisations.
"Our findings provide important evidence that booster shots are highly effective and those who are unvaccinated are at significantly greater risk of experiencing more severe Covid-19 outcomes and should get vaccinated and boostered as soon as possible," researcher Shaun Grannis from Indiana University, said.
The value of the third dose of an mRNA vaccine is significant as two doses were only 38 per cent effective in protecting against Omicron-related ED visits and only 57 per cent effective in protecting against Covid Omicron variant-related hospitalisations.
Boosters were even more effective against the Delta variant of Covid, protecting against 94 per cent of both Covid Delta variant associated ED visits and hospitalisations.
The CDC collaborated with six US healthcare systems to create the VISION network to assess Covid vaccine effectiveness.