What's new with COVID-19 and Flu?

Dr. Brian Metzger, medical director of infectious diseases at St. David’s HealthCare, answers questions about the 2024/25 virus season and vaccines.

What strain of COVID-19 is currently circulating? 

We are still seeing SARS-CoV-2 strains in the Omicron family. Earlier this summer, a subvariant called JN.1 was predominant, which later shifted to KP.2 and then KP.3.1.1. COVID-19 is a constantly moving target, with new Omicron subvariants arising frequently.

How are this year’s COVID-19 vaccines different from last year’s?

Like the flu vaccine, the COVID-19 vaccine is adjusted periodically based on the most prevalent strain causing illness. The new COVID-19 vaccines target a strain that peaked in June called KP.2, which is a subvariant of Omicron. These vaccines still provide protection against severe illness from COVID-19.

There is overwhelming evidence that we will see continued movement to different strains within the Omicron family. This is primarily due to the fact that Omicron has been the most transmissible of all the variants. There is so much immunity in the population with prior infection and vaccination, it would take a variant that is more transmissible and resistant to that immunity to take over.

What is the likelihood that this year’s COVID-19 strains will cause severe illness?

There are still cases of severe illness, but it’s not like what we were seeing before vaccinations. More severe illness with COVID-19 is affecting mainly immunocompromised populations and individuals with comorbidities, such as lung disease or cardiovascular disease. 

What about the flu? Will this year’s flu season be a bad one?

Every year, we worry about influenza because of the burden of illness it causes. Flu vaccines help quite a bit with decreasing severe illness, but it won’t entirely prevent you from getting the flu. Just as the COVID-19 vaccine prevents severe illness, you can still get infected with the virus. Based on the experience in the southern hemisphere, we are expecting an average flu season similar to last year.

Who should get the COVID-19 and flu vaccines at the same time? 

This is very much a personal choice. It’s been well proven that the COVID-19 and flu shots can be given at the same time. If you’re someone with limited healthcare contacts, or someone who can’t go back for another appointment for a while, it’s better to get both vaccines at once. We encourage everyone to get their COVID-19 and flu vaccines before the end of October. 

How far away are we from getting a combined vaccine for COVID-19 and flu?

Researchers are getting closer to creating a combined vaccine that’s safe and effective. It’s not imminent, but it's possible we will have one next season.