The R.S.V. surge

By Jonathan Wolfe for The New York Times |

A drastic and unusually early spike in infections caused by the respiratory syncytial virus, known as R.S.V., is overwhelming pediatric units across the U.S. Patients are experiencing long waits for treatment and hospital systems are rearranging staffing and resources to meet the sudden demand.

R.S.V. is also on a collision course with two viral diseases — Covid-19 and the flu — and experts say that we could see simultaneous surges this winter. Of the three threats, R.S.V. is the most mysterious to many. A lot of Americans are still in the dark about the virus and what to do about it.

For insight, Jonathan Wolfe spoke his colleague Apoorva Mandavilli, who covers infectious diseases.

How serious is R.S.V.?

It’s not as serious as Covid, but it’s looking like it might be almost as serious as influenza, and that we just haven’t known about it.

Part of the problem is that doctors didn’t know that R.S.V. was a risk for adults, and so they weren’t really testing for it. One of the doctors I talked to said: “Why would we test for it? There was no treatment, there was nothing we could do, so what would be the point?” So we have a dimmer view of how prevalent it is among adults than we do for influenza.

What about for children?

It’s most serious for infants and children under 5 in general, and it plays a pretty big role in infant mortality worldwide. It’s most risky when they live in countries where there isn’t easy access to oxygen or other things that can help.

In most richer countries, when kids go to the hospital with R.S.V., they come out pretty quickly because they get help with breathing or whatever they need. In the U.S., about 200 to 300 children die from R.S.V. a year, compared to 100,000 worldwide.

It’s important to know that it can also be fatal for older adults, too. About 14,000 older adults in the U.S. die from it each year. It’s also more serious for pregnant women and immunocompromised people.

What does R.S.V. do to the body?

It’s very similar to other respiratory viruses. It basically infects your airway cells, and it’s particularly bad for the lower respiratory pathway. In children, R.S.V. really hits the lungs hard, which is why they can have such difficulties breathing.

But the virus actually has a pretty short trajectory in the body. As with Covid, it’s not always the virus but the inflammation that your body produces that can be damaging. That’s especially true when R.S.V. infects older people and children.

Why are we hearing so much about R.S.V. now?

For pediatricians and parents, R.S.V. is not new. But this year, we just have many more infants who have had no exposure to R.S.V. They are either babies who were born during the pandemic, when there was very little R.S.V. around, and didn’t develop immunity, or babies who were born right before the pandemic and didn’t build up immunity like children normally would in the first few years of life. And because they’ve had so little exposure, it also means that when the virus does attack them, it can manifest more severely.

Where are we with a vaccine?

A vaccine has been really hard to make. There’s a part of the virus — kind of like the spike protein in Covid — that binds to the receptor of human cells. And scientists just could not get the vaccine to block that part of the virus. There was also one R.S.V. vaccine, decades ago, that went really wrong. Children in the trial who got the vaccine did much worse when they got infected with R.S.V. later. That really freaked out people in the field, and everyone kind of stayed away from it because of that.

But then in 2013 there was a breakthrough. Researchers at the National Institutes of Health figured out how to target the virus. After that, as people started to realize that R.S.V. was a threat for older adults too, the market size for a vaccine grew and more companies became interested and invested.

So where are we now?

Things are actually looking great. We have a bunch of vaccine candidates for adults that are doing really well. GSK had late-stage clinical trials finish earlier this year, and their results looked great in terms of severe disease. It looks like the vaccine may be approved within a few months.

Pfizer also has a vaccine in clinical trials to protect infants. Their results show that the vaccine is not fantastic against infection, but it looks pretty good against severe disease and hospitalization. It looks like both vaccines, as well as another one that Pfizer is developing for adults, might be available by next fall.

What’s the best way to protect ourselves from R.S.V.?

It’s mainly older adults and parents who have to really worry about this. I would say that parents need to keep an eye on their children. If they see that their kids develop a fever and look like they may have any trouble breathing, they should immediately bring them to the doctor or even to the emergency room.

Also, wash your hands and wear a face mask if you can because there is a lot of R.S.V. around, especially if you’re immunocompromised. Adults who are sick should definitely avoid contact with anybody who might be at risk. Even if you have a cold, and you only have minor symptoms, it may be pretty serious for somebody else.