Influenza Season and the Complexities of COVID-19 and Evolving Variants
What you need to know to prepare for influenza season, including COVID-19 testing
How was last year’s influenza unique?
The last season was a bit of an outlier. There were many public health countermeasures put in place for COVID-19, and I think that had a significant impact on influenza rates. We did not see a spike in seasonal influenza cases as we often do between November and February each year. But just because we didn’t see many cases, does not mean influenza is gone. As we begin to open up the economy and return to more crowded settings, it is possible we will see a rebound in influenza cases in 2021.
What do we need to know for this upcoming influenza season?
We must expect that influenza will return this year, and prepare accordingly. The big question that remains is whether the influenza virus has evolved since it was essentially dormant last year. We have no surveillance data from last year, and there is the possibility that it will be a worse influenza season compared to 2019. Given the unknowns, it is probably best to prepare for a worst-case scenario.
Are there options that will enable testing for both COVID-19 and influenza?
Yes. When the pandemic began, diagnostic test manufacturers were mainly focused on developing a test for COVID-19. By the fall of last year, preparations were already underway to develop multiplex tests for COVID-19 and influenza. As a result, we have real-world evidence demonstrating that these assays work, and we know we have sufficient manufacturing capacity. We are heading into the upcoming influenza season prepared for testing.
Will there be changes to how the influenza vaccine is administered this winter?
Vaccines for COVID-19 and influenza will likely be administered separately this winter. There is research underway examining combination vaccines for both of these viruses, but I think it is unlikely they will be available this year. It is also important to note that some COVID-19 vaccines use mRNA technology, while the influenza vaccines are inactivated/attenuated virus vaccines. There should be some interesting studies to see if and how these technologies will be used for combination vaccines.
Is it possible that emerging COVID-19 mutations will cause more reinfections and require updated vaccines?
Mutation is a significant risk. I think what we are doing right now with COVID-19 vaccines is creating evolutionary pressure on the virus. The virus will find a way to evolve and will not be eradicated—it will become endemic. There was concern with the Delta variant that the vaccine would be ineffective. Thankfully that was not the case, but as mutations accumulate, at some point the threshold will be met, and a new variant could emerge that could be resistant to the vaccine. Surveillance testing will be very important to identify these variants. Fortunately, mRNA technology should make it relatively easy to quickly modify vaccines with new variant sequences.