[nudephil (OP)]

Here's a question we got from Alastair:

With the huge reduction in air travel - plus global efforts to socially distance, wear masks, etc., to reduce transmission of the coronavirus - why is it that the flu virus is still expected to have the same (or worse) impact as an average year? Given that seasonal flu typically spreads from East/Southeast Asia, shouldn’t these measures also significantly reduce flu transmission? Or is it more virulent than SARS-Cov-2?

Can anyone answer?

[evan_au]

I think that reduced air travel will slow down spread of influenza this year (but not stop it).
- Quarantine, social distancing and masks means that we will flatten the influenza curve (but not stop it)

In Australia, the SARS-COV2 pandemic was used as an excuse to promote flu vaccination: you were not permitted to visit residents in aged care unless you had flu vaccination.

A rationale for this is that influenza and SARS-COV2 are superficially similar: a viral respiratory disease with possible complications from pneumonia.
- If someone already has SARS-COV2, you could expect that catching influenza too will make their condition far worse (and vice versa for someone with influenza catching SARS-COV2).
- If someone has a severe respiratory disease, do you admit them to the COVID-19 ward, or the influenza ward? Making the wrong decision could be catastrophic for everyone!

[Bored chemist]

why is it that the flu virus is still expected to have the same (or worse) impact as an average year?

Who says it is?

[evan_au]

This article suggests that:
- Australia almost missed the flu season this winter (now just ended in the southern hemisphere). Social distancing, travel restrictions and a big vaccination campaign undoubtedly helped!
- Rhinoviruses are still circulating because they are more resistant to hand washing and hand sanitizers.
- SARS-COV2 has a fatty layer that is dissolved by washing with soap.

See: https://www.scientificamerican.com/article/why-some-people-are-still-getting-sick-but-not-with-covid

[evan_au]

This article has graphs showing that flu cases were dramatically reduced this year, largely due to COVID-19 protection measures:
https://www.scientificamerican.com/article/flu-season-never-came-to-the-southern-hemisphere/