The study, jointly conducted by the medical schools of The University of Hong Kong and The Chinese University of Hong Kong, highlighted the need for Covid-19 vaccination for unvaccinated people even after infection.

The conclusion came after researchers from both universities studied the virus neutralizing activity in the blood of vaccinated individuals after an Omicron, BA.1 or BA.2, infection.

The findings show that an Omicron infection in unvaccinated people can only induce very weak antibody responses, which react with Omicron only.

“In contrast, a breakthrough infection caused by Omicron in fully vaccinated individuals leads to a more potent antibody response, which is six times higher than those of unvaccinated patients.”

“More importantly, such an antibody response found in vaccinated individuals is broadly reactive and it can react with other variants of concerns, such as Beta and Delta,” the study noted.

David Hui Shu-cheong, Professor of Respiratory Medicine at CU Medicine, urged people not to assume that an Omicron infection could induce strong immunity to protect against future Covid variants.

“These [unvaccinated] patients are highly recommended to get vaccinated after full recovery from infection- [that is] at least one month or more after the infection,’ said Hui.