Are We Going to See a Summer Surge of RSV This Year?

Folks need to understand that RSV might still be coming. If not in the next few months, then maybe this summer. And if there is no summer surge of RSV, then it will likely be back even worse next year.

A summer surge of RSV?

I know, it sounds ridiculous, right?

After all, in a typical year, RSV season begins in September or October and peaks in December or January.

Of course, this hasn’t been a typical year…

Are We Going to See a Summer Surge of RSV This Year?

Except for COVID-19, rhinovirus, enterovirus, and some adenovirus, we haven’t seen most of the seasonal viral outbreaks that we typically see each year.

There hasn't been any RSV in Texas this year.
There hasn’t been any RSV in Texas this year.

There was no RSV, flu, or seasonal coronavirus, etc.

Not that anyone has been complaining…

It was one of the bright spots that came out of all of the social distancing, mask wearing, and travel restrictions to control the COVID-19 pandemic!

So why would anyone think that we might see a summer surge of RSV?!?

The news that folks in Australia started getting hit with RSV a few months ago, when it was still summertime!

Remember, Australia is in the Southern Hemisphere and their summer runs from December to February and their autumn from March to May.
Remember, Australia is in the Southern Hemisphere and their summer runs from December to February and their autumn from March to May.

What caused the summer surge of RSV in Australia?

An unexpected surge that is also being reported in South Africa

“Recent reports from Australia described an inter-seasonal RSV epidemic in Australian children following the reduction of COVID-19–related public health measures from September 2020 to January 2021.”

Delayed Start of the Respiratory Syncytial Virus Epidemic at the End of the 20/21 Northern Hemisphere Winter Season, Lyon, France

Is it because they got their COVID-19 cases under good control early and relaxed many of their COVID-19 related public health measures, including eliminating mandates to wear masks and most restrictions on public gathering, and allowed kids to go back to school?

Whatever the reason for the surge, what is most troubling is that we may not have to wait until this summer for our own surge!

“In 2020, the first RSV cases of the 20/21 season were detected in Lyon at week 46 and 47 (Figure 1) at the same time of the southern hemisphere outbreak. A sustained detection of cases was observed from week 51, which is the expected time of the epidemic peak, to week 5. On week 6, the RSV epidemic was declared in the first French region (Ile de France) while the number of RSV cases has continued to increase in the Lyon population.”

Delayed Start of the Respiratory Syncytial Virus Epidemic at the End of the 20/21 Northern Hemisphere Winter Season, Lyon, France

France is seeing RSV too – with a 4 month delay to the start of their season. And they haven’t relaxed their physical distancing recommendations as much as Australia, as they were still seeing cases of COVID-19.

And as if all of that wasn’t enough, the summer surge of RSV in Australia is at rates that are much higher than is seen in a typical RSV season!

Wasn’t that expected?

“Our results suggest that a buildup of susceptibility during these control periods may result in large outbreaks in the coming years.”

The impact of COVID-19 nonpharmaceutical interventions on the future dynamics of endemic infections

While larger future outbreaks have been expected, most people likely thought they would start with next year’s season.

“Our findings raise concerns for RSV control in the Northern Hemisphere, where a shortened season was experienced last winter. The eventual reduction of COVID-19–related public health measures may herald a significant rise in RSV. Depending on the timing, the accompanying morbidity and mortality, especially in older adults, may overburden already strained healthcare systems.”

The Interseasonal Resurgence of Respiratory Syncytial Virus in Australian Children Following the Reduction of Coronavirus Disease 2019–Related Public Health Measures

I’m not sure anyone is ready for RSV and COVID-19 at the same time. That’s not the Twindemic folks were warning us about!

But maybe we should get ready to start seeing some RSV.

March is typically close to the end of RSV season, not the beginning.
March is typically close to the end of RSV season, not the beginning.

After all, rates of RSV are starting to increase in Florida and the South Atlantic division of the United States.

While there is no way to know if we will see this trend in other states and we may just be delaying when RSV season starts anyway, parents should know that we can always protect those who are most at risk from severe RSV disease.

“Ideally, people with cold-like symptoms should not interact with children at high risk for severe RSV disease, including premature infants, children younger than 2 years of age with chronic lung or heart conditions, and children with weakened immune systems.”

RSV Prevention

At some point, we might even have to consider changing when Synagis, the monthly shot that can help prevent RSV, is given. Should we continue giving Synagis to high risk infants this Spring and Summer, for example, instead of stopping in March?

Mostly, folks need to understand that RSV might be coming. If not in the next few months, then maybe this summer. And if not this summer, then it will likely be back with an even worse next year.

More on RSV

Author: Vincent Iannelli, MD

Vincent Iannelli, MD