For the past 18 months most of the world's population has been shielded from common winter respiratory viruses - like influenza, RSV, and Rhinoviruses - due to the combined effects of social distancing and personal protective measures (i.e. facemasks), and `viral interference' caused by the COVID virus itself.
There are growing concerns, however, that - between the resumption of school and the abandonment of many personal COVID protection strategies (i.e. facemasks, social distancing, etc.) - that many countries will face a potential `twindemic' of COVID and winter respiratory viruses (including Influenza, RSV, etc.) this fall or winter.
As we've discussed previously (see here, here, here, and here), our lack of exposure to common respiratory viruses is a double-edged sword.- In the short run, it makes it easier to identify COVID cases, lessens the burden on healthcare delivery systems, and avoids the enhanced risks due to dual infections.
- But at the same time, this lack of exposure allows our community immunity to these viruses to wane over time, potentially setting us up for serious epidemics when they finally do return.
Over the summer we've followed a marked increase in RSV - both in the United States (see CDC HAN) and in places like New Zealand, Denmark, and the UK - despite this being the `wrong-season' for RSV for most of these countries.
UK PHE Warns On A Summer Uptick in RSV InfectionsSSI: Denmark Also Reporting A Summer Surge In RSVThese increases have coincided with the lessening of COVID social distancing restrictions, and have raised concerns - including mid-July's UK Academy Of Medical Sciences: Looking Ahead To COVID-19 Over Winter 2021/22 & Beyond and a commentary appearing in the CMAJ called Potential resurgence of respiratory syncytial virus in Canada - that we could face a challenging winter ahead.ESCMID: When Respiratory VIruses Return & New Zealand's RSV Resurgence
The full (translated) report follows.Today we have another warning - again from Denmark - of what they describe as an `Absolutely extraordinary' off-season spike in RSV cases.
Absolutely extraordinary many are getting RS virus right now
Since week 20, 1,734 cases have been detected. Most in children between 1-3 years.
Last edited September 3, 2021
Usually, the respiratory infection RS virus is something we see most in winter. However, this is not the case this year. Right now, there are an extraordinary number of cases of RS virus in Denmark.
This is shown by the latest figures from the Statens Serum Institut (SSI)
The summer epidemic with the RS virus already began to develop earlier in the summer (LINK TO EPI-NEWS 27/21). In recent weeks, however, the infection has risen sharply.
In week 34 alone, 510 cases were detected. This is almost 30% of the total 1,734 RS virus cases detected since week 20. Most in children between 1-3 years.
More widespread infection
Although fewer patients are currently being tested for the RS virus than during a normal winter season, the infection is just as widespread.
"It shows two things: First, that the infection right now can be significantly more widespread than during the normal season in winter. Partly that doctors must pay special attention to RS virus and make sure that patients are tested if they have symptoms of the virus ", says ward doctor Lasse Skafte Vestergaard from SSI.
Perhaps due to the reopening
It is not known for sure why there are unusually many cases of RS virus in Denmark right now. But the same picture is seen in several other countries.
"A possible explanation may be that it is an effect of the fact that the country has recently been reopened after the closure and restrictions during the covid-19 epidemic. And that there are therefore more people traveling, ”says Lasse Skafte Vestergaard. He continues:
"It may also be that right now there is less immunity to the RS virus among children, because there were far fewer cases of the virus in winters. Here we saw a sharp drop in both RS virus and a number of other respiratory infections due to the covid-19 restrictions and hygiene precautions. ”
Read more
Read more about RS virus right now (LINK TO EPI-NEWS 35/21)
Facts about RS virus
- RS virus is the most common cause of young children being admitted with a respiratory infection.
- Often the infection progresses as a cold. But especially in young children under 6 months, a lower respiratory tract infection is often seen, which leads to breathing problems.
- By the age of 2, almost all children have had the RS virus once. And half have had it twice.
- In Denmark, approximately 3% of all children are admitted with the RS virus at least once within the first two years of life.
- The risk of hospitalization is significantly higher in children who are born prematurely, have heart or lung disease or who suffer from other chronic conditions. However, it is extremely rare for any Danish children to die from RS virus infection.
The feared `twindemic' of COVID and influenza wasn't realized last year, and perhaps we'll get lucky again this year. But we are in uncharted territory, and nobody knows exactly how COVID - and other respiratory viruses - will play together in the months ahead.
We do know that even without a pandemic strain, influenza can sometimes deliver a hellish flu season, as it did in over the winter of 2017-18 (see 2018's CDC: The Estimated Burden Of Last Year's Flu Season).
The good news is, there are simple things we can do to reduce the impact of influenza, and other seasonal respiratory viruses, when they eventually do return.
- We can get the yearly flu shot,
- We can continue to wear face masks in public and avoid crowds during outbreaks
- We can be scrupulous in our hand hygiene
- And we can choose not to go to work, school, or out in public if we are `sick'.
Lest you think the public wearing of face masks beyond the pandemic is impractical, their use has been common practice in Asian countries for years, long before COVID emerged (see 2019's HK CDW: Surgical Masks For Respiratory Protection).
Figure 2 - How to wear a surgical mask. (Source: The Centre for Health Protection of the Department of Health.We know how to save thousands of lives each year, and at the same time reduce the burden on our healthcare delivery systems.
