Q and A with experts: What to know about the new COVID-19 variant and updated vaccines

As new COVID-19 variants continue to appear, many Canadians are wondering whether the updated vaccines still offer strong protection. Dr. Yangjianchen Xu, a professor in the Department of Statistics and Actuarial Science at the University of Waterloo and co-author of a large study involving 1.8 million participants, explains how the virus is evolving, what the data show about vaccine performance and why staying up to date with vaccination continues to matter. 

University of Waterloo professor Dr. Yangjianchen Xu.

 
What makes the new variant different? 

The new JN.1 subvariants of COVID are descendants of earlier Omicron strains and continue to evolve, showing mutations that help the virus partially evade immunity from prior infection or vaccination. However, our study involving 1.8 million Nebraska residents showed that while the virus has changed, its behaviour remains predictable in one key way: vaccines continue to reduce the risk of severe outcomes such as hospitalization and death. 
 

How effective is the current vaccine against new variants? 

Our findings show that the updated vaccines remain clearly effective. The vaccines reduced the risk of symptomatic infection by 44.7 per cent at four weeks after vaccination, declining to 16.7 per cent at 20 weeks. The risk of an emergency department visit dropped by 45.1 per cent at four weeks and remained at 39.1 per cent at 20 weeks. Most importantly, the vaccines reduced the risk of hospitalization or death by 57.3 per cent at four weeks and 34.0 per cent at 20 weeks. 
 

Why is it still worth getting vaccinated? 

There are several compelling reasons to stay up to date with vaccination. Even if breakthrough infections occur, vaccinated people are far less likely to experience severe illness, require intensive care, or die from COVID-19. Vaccination also reduces the likelihood of developing long COVID, meaning fewer long-term complications and disabilities. 

From a community perspective, boosters lower overall transmission pressure, helping protect vulnerable populations such as older adults and those who are immunocompromised.        
 
This series is produced for the media, with the purpose of sharing the expertise of UWaterloo researchers. To reach this researcher, please contact Media Relations.