COVID, RSV, and Kids

Oh my shit.

A recent preprint looks at the role COVID played in the massive surge of childhood RSV cases–and it wasn’t just immunity debt (lack of exposure to RSV due to COVID precautions). Here’s a disturbing graph:

Screenshot 2023-07-04 at 10.56.12 AM

You can see how COVID precautions prevented the annual November 2020 to February 2021 peak–and relaxing those precautions led to an ‘out of cycle’ peak in mid-2021. What’s disturbing though is the massive 2022 surge. If you look at the bottom panel which describes the patterns for kids under one year old–and these are kids for whom immunity debt doesn’t apply as they are always too young to be previously exposed–we see a massive surge in them too. But is this due to COVID? Comparing balanced cohorts of children, the authors conclude (boldface mine):

In 2022, medically attended RSV infection including both clinically diagnosed severe RSV diseases and positive lab test-confirmed infections reached a historically high rate, higher for severe RSV diseases than the positive lab test-confirmed RSV infection. Among children aged 0–1, the peak incidence rate of severe RSV-associated diseases in November 2022 was 2,285 cases per 1,000,000 person-days, 47% higher than lab test-confirmed RSV. These data suggest that the 2022 RSV surge was disproportionately driven by more severe cases of RSV diseases, which could not be fully explained by increased testing practices, awareness, or transmission through day-care or siblings alone. While nonpharmaceutical interventions in 2021 and immunity debt contributed to the increased rate of RSV infection, these factors alone could not fully explain the huge surge in November 2022, representing 4–5 times as many severe RSV-associated diseases as in 2021. For children aged 0–1 year (as of 2022), if the immune debt due to waning maternal immunity was the main contributor, we would expect that the level of RSV infection in 2022 to similar to that in 2021. Instead, the peak incidence rate of severe RSV diseases in children aged 0-1 year was 2,285 cases per 1,000,000 person-days in November 2022, a 161% increase compared to the peak rate of 874 cases per 1,000,000 person-days in August 2021. The comparisons between matched COVID-19 (+) and COVID-19 (–) cohorts showed that prior COVID-19 infection was associated with increased risk for RSV infection in 2022. In 2022, significantly more children contracted COVID-19 due to the relaxation of preventive measures and the dominance of the highly transmissible Omicron variant. Together with the effects of RSV-specific immunity debt and other factors, the large buildup of COVID- 19-infected children and the potential long-term adverse effects of COVID-19 on the immune and respiratory systems may have contributed to the 2022 winter surge of severe RSV diseases.

In fact, kids in the COVID positive cohort were about 40% more likely to contract RSV, depending on the exact metric used.

This isn’t the only such observation to find a link between COVID and elevated risk for other infectious diseases: an Israeli study found that kids who had COVID were more likely to contract Streptococcus infections three to six months later.

The point isn’t that ALL THE KIDS HAVE TEH AIDS!!! But these sorts of changes can (and do) completely overwhelm medical systems:

The good news is that this elevated risk in kids isn’t very high in absolute terms: it’s around 0.5%*. That said, the absolute effect averages across seasons; if the increase is concentrated at certain times of the year, that ‘surge’ will be difficult to handle. From a public health perspective–in particular, keeping hospitals from being overwhelmed–is that “1-most” (which is the percentage of sick kids) is very dependent on the size of most: small changes in the likelihood of illness can overwhelm hospital capacity, even though most kids will still be fine (not require hospital treatment).

In this case, we’re still talking about an absolute increase of one to two percent of all kids who require medical attention due to RSV. That is not good for those kids, and that is not a trivial increase in serious childhood illness.

No, COVID doesn’t cause ‘AIDS’, but it isn’t good for kids health either. So you’re not the weirdo if you’re trying to limit your exposure to COVID.

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