New study shows boosters and public health measures limit omicron spread

New research has highlighted the importance of boosters and public health measures in protecting the population against the COVID-19 Omicron variant.

The study by the National Centre for Immunisation Research and Surveillance (NCIRS) examined two indoor events in Newcastle, New South Wales at the start of the Omicron outbreak. 

The events were attended by a young population with very high double-vaccination rates but where social restrictions were absent. There was no mask wearing, no strict control on density limits and activities conducive to virus transmission occurred, including dancing, drinking and close face-to-face contact.

Associate Professor Bette Liu, the study’s lead author from NCIRS and UNSW, said the study provides valuable information supporting the need for public health and social measures to limit the spread of Omicron. 

Our findings suggest that while recent vaccination with two doses was moderately effective in preventing infection with the Omicron variant, this varies depending on the setting. Social restrictions are needed in high-risk indoor environments, in addition to two doses and a booster, to reduce infection risk.

“At both of the Newcastle indoor entertainment venues, one a nightclub and the other a ball, at least 95 per cent of people had two doses of a COVID-19 vaccine but of those followed-up approximately 55 per cent tested positive,” A/Prof Liu said.

However, because of the high-risk setting and their young age, the findings cannot be translated to other environments or compared to the general population.

Prof David Durrheim, Health Protection Director, Hunter New England Local Health District said the study, as well as data from the UK and South Africa, shows the importance of boosters.

“While we can see moderate protection against hospitalisation for the Omicron variant following two vaccine doses, protection wanes from 2 to 3 months after the second dose but is increased significantly following a booster,” he said. 

Our study adds to the evidence that public health measures and restrictions coupled with recent booster vaccination are the best way to keep our community safe.

The study is a pre-print report not yet peer-reviewed and can be read in full here.