Hybrid immunity is 'best protection' against COVID-19, study finds

This colorized electron microscope image made available by the National Institute of Allergy and Infectious Diseases in November 2022, shows cells, indicated in purple, infected with the omicron strain of the SARS-CoV-2 virus, orange, isolated from a patient sample, captured at the NIAID Integrated Research Facility (IRF) in Fort Detrick, Md. (NIAID/NIH via AP)

A study, published by the University of Calgary in partnership with the World Health Organization (WHO) has found anyone who has at least the full set of COVID-19 vaccinations and a prior infection has the best chance of prevention of future infection.

The document, which was published in The Lancet on Wednesday, will help medical professionals make decisions on optimal courses of vaccination.

"A common question throughout the pandemic was whether previously infected people should also get vaccinated. Our results clearly indicate the need for vaccination, even among people that have had COVID-19," said Dr. Niklas Bobrovitz, one of the study's authors, in a statement.

The research was built on data collected during the Omicron wave, which prompted a more detailed look at the public's protection against infection and severe disease.

Researchers say those who had been infected COVID-19 and were properly vaccinated against it had 95 per cent protection against the virus for a year.

Past that point, it was discovered that protection against Omicron "declines substantially."

"(That) means that vaccination is the best way to periodically boost your protection and to keep down levels of infection in the population," a statement from the U of C reads.

The data collected in the study will help protect the population against future waves of COVID-19, researchers say.

"We know more variants are going to emerge," said Dr. Lorenzo Subissi with the WHO, a senior author for the study.

"The study shows to reduce infection waves, vaccinations could be timed for roll-out just prior to expected periods of higher infection spread, such as the winter season."

'VIRUS IS UNPREDICTABLE'

If you haven't contracted COVID-19, the study's research team says this finding shouldn't be taken as advice that you should intentionally infect yourself.

"The virus is unpredictable in how it will affect your system," said Bobrovitz.

"For some, it can be fatal or send you to hospital. Even if you have a mild infection, you risk developing long COVID."

The phase of the study will be to look at the effectiveness of the bivalent vaccine against severe disease.