Additionally, because most people mount a good immune response to the vaccine, which might make them feel sick, getting the vaccine when you’re actively infected can worsen symptoms and place more stress on your body. .
A December 2021 study from Israel, also published in The New England Journal of Medicine, showed that vaccine effectiveness decreases six months after the second Pfizer-BioNTech dose, making vaccine immunity less protective against any coronavirus variant. .
One study published to the preprint database medRxiv but not yet peer-reviewed found that a two-dose mRNA vaccine regimen provided no protection against infection with omicron.
But vaccine effectiveness increased to 37% one week after an mRNA booster, that research found. .
No matter which vaccine you started with, it's important to get a booster once you're eligible, Johnson said. .
"People who've just had the primary series are still very much at risk for infection with omicron, though their infection might not be severe," Johnson told Live Science."But for people that have received the booster dose, that seems to offer effective protection against omicron infection and certainly against more severe disease.".
Either way, being infected with omicron is not a good reason to avoid getting boosted, Johnson said"Vaccination with a booster dose is absolutely necessary to achieve the best protection possible," Johnson said