Health Wanted Show Notes: Winter Respiratory Viruses
Fall is imminent, and with it comes the start of respiratory virus season.
There are so many different germs preparing to enter the warm comfort of your nose, throat, and lungs, so let’s review our plans for staying in good health as the temperatures decrease.
As always, let’s start with the basics: what is a respiratory virus?
It’s any number of viruses that can infect the cells of your upper or lower respiratory tract and cause illness.
For a quick refresher, Your upper respiratory tract is your nose, sinuses and throat (larynx and pharynx), and your lower respiratory tract is the stuff below your airway. So, your trachea, bronchi and lungs.
Of course, other things can cause disease, too. For example, strep throat is caused by bacteria. But we’re not going to talk about those right now, we’re going to talk about viruses.
And because we’re going to talk about viruses, I want to get you all in the habit of good antibiotic stewardship, so say it with me: “you cannot treat a virus with antibiotics.”
Unfortunately, we are living in a time where more and more bacteria are becoming resistant to the antibiotics that once treated them.
This is largely due to the over-prescribing of incorrect antibiotics. Instead of killing the bacteria, it gave bacteria the opportunity to adapt.
So please, don’t go to your doctor asking for antibiotics if you don’t know whether you’re suffering from a bacterial infection or a viral infection.
And the last of these technical notes: pneumonia is an infection of the lungs that causes the air sacs to fill with fluid. It can be caused by bacteria (in which case you’d get antibiotics) but it can also be caused by viruses or even fungi, which would not be treated with
Ok now that that’s out of the way…let’s see what’s in store for us this winter!
Let’s start with what currently ails us: COVID-19.
It feels a bit weird to talk about COVID as a potential winter respiratory virus of concern given that we are currently in a huge summer spike, but both things can be true at the same time!
Tracking COVID cases in the community has always been a tricky endeavor. Not everyone was testing at sites that reported numbers, then states began to change how and if they reported numbers, and now with home tests a lot of cases aren’t being reported at all.
So now, we have to turn to wastewater to get a sense of how much COVID is circulating in the community.
As of late August, the levels of COVID in wastewater are at about 60% of what they were during the height of COVID last winter.
At various points in the summer, you may have heard (or more likely read on social media) estimates of the number of new cases of COVID a day in the U.S. These numbers come from a model that uses wastewater estimates.
Basically, it’s a prediction about information we do not have (the true number of COVID cases) that’s created from information we do have (the amount of COVID genetic material in wastewater).
We have a saying that goes, “all models are wrong, some models are useful.” What this means is that modeling is very detailed, structured, and thoughtful guessing…but it’s still guessing.
I don’t want anyone to think I’m being dismissive of the amount of COVID circulating; I have no doubt it’s a lot. But I do have some questions about these models that haven’t been answered, like:
How you can account for new cases of COVID per day when people can shed the virus long after they stop being infectious?
When we talk about public health, I think it’s really important we talk about limitations to knowledge as well.
Stating uncertainties as facts can cause people to feel paralyzed with fear instead of empowered to take action to change our circumstances.
One such action you could take to change our circumstances is to get the new COVID vaccines, some of which are now available.
The new shots from Pfizer and Moderna target the KP.2 variant, which you may have heard talked about as the FLiRT variant earlier this spring.
The shots from Novavax will target the JN.1 variant.
But how do vaccine manufacturers figure out which COVID variant to target? Well, that brings us to our weekly visualization:
Picture a tree. The trunk of the tree is the original strain of SARS-CoV-2 that came to the United States in early 2020.
Each branch that grows from this trunk is a different variant of COVID. Some branches break off into more branches and twigs, and some just end.
As we travel up the trunk, we’ll pass a branch that was the Delta variant, that caused a wave of cases in summer of 2021.
If we keep going up the main part of the tree, we can travel down the branch for the original Omicron spike that peaked in early 2022, which will eventually separate into branches of the variants we used to update the last two vaccines.
But we are going to continue along this omicron branch until we get to where it splits and takes us to 1
This is the branch we care about because it’s both the branch that has the variants that were used to make the updated vaccines, and the branch that has the most commonly circulating variant right now.
And unfortunately, those two things are not the same thing—predicting what COVID variant will be the most prominent 3 months ahead of time is hard! The virus has shown that it mutates with ease.
There are 4 variants that account for 82% of all COVID cases right now, and while none of those 4 are the exact variant that was used to create the vaccines, they are all closely related.
If we think of it like a family tree, JN.1 (the variant that Novavax based their vaccine on) is like the grandpa, and KP.2 (the variant that Pfizer and Moderna used) is his son.
In regard to the top 4 variants that are circulating right now, they all run the gamut of being either siblings, grandchildren, or nieces and nephews to the two variants use to build the vaccines.
Basically, they’re not an exact match, but all close enough to be invited to the same Thanksgiving.
As for when to get the vaccines, that depends on your personal circumstances. We know that protection from the vaccines wanes over time.
COVID levels are still very high, but it does take two weeks to build your antibodies after the dose, so the wave of COVID might be descending by then.
If you have upcoming travel or events, it might be worthwhile to get the vaccine now. I’m personally planning to wait to get it with my flu shot around mid-October to set me up for the winter season.
If you’re someone who’s had COVID recently, the CDC says you can delay your vaccine for 3 months after your infection.
I’d personally recommend everyone get it by Halloween.
And if you’re wondering WHY you’d get an updated vaccine, as a fit young buck, aside from the fact that they reduce your risk of getting sick, and protect from severe disease, we now have multiplestudies that show the risk of long COVID is dramatically decreased with vaccination, though not eliminated entirely.
Now feels like a good time to do a short reflection on the state of COVID in the U.S.
We are in a drastically different position today than we were in 2020, or even in 2022. The CDC recently released provisional mortality data relating to COVID for 2023.
The rate of COVID as an underlying or contributing cause of death was 69% lower in 2023 compared to 2022.
COVID also moved from the number four cause of death among adults in the U.S. in 2022 to the number 10 cause of death in 2023.
The reason for this is mixed immunity from vaccines and exposure.
Only 22% of adults reported getting an updated vaccine for the 2023-2024 respiratory virus season. If we can increase that number, I do think we can get COVID out of the top 10 altogether.
Of course, death is not the only outcome of COVID.
Long COVID is a topic that really deserves a whole episode to update, but in the meantime, I still want to acknowledge it.
The most recent CDC census estimates that 5% of all adults in the U.S. are currently experiencing long COVID, which is down from over 7% in the summer of 2022. And while it’s great that it seems to be stabilizing, it’s still far too many people.
Those people deserve care, compassion, and, most importantly, research and support to help them.
We have come a long way and we still have a long way to go.
Another virus to keep an eye on this fall and winter is one you might not even know about: Human parvovirus B19.
While similar in name to the disease that kills dogs and cats, this one is for the humans (and can’t be passed from owner to pet or back).
This version of parvovirus is highly contagious and spread by droplets, like the flu.
Many people can be asymptomatic, but for kids who develop symptoms it can also be known as “slapped cheek disease” for the distinct red rash that develops on the face, or “fifth disease” creatively named because it is the fifth disease on the list of six viral diseases known to cause skin rashes on children. It follows measles, scarlet fever, rubella and Duke’s disease.
The virus is most prominent in kids aged 5-9. It’s typically seasonal in the winter, spring and early summer months, but has minor outbreaks every 3-4 years as the pool of young children without previous exposure grows.
The proportion of kids 5-9 years old who have antibodies that suggest a recent infection was 10% from for the last two years but in June of 2024 jumped to 40%.
So, cases are on the rise. Many children won’t have symptoms, but those who do get sick have muscle aches and pains, cough, sore throat, and then that facial rash that can turn into a body rash and joint pain.
By the time the rash comes around they’ve stopped being infectious.
Most people are fine, and severe complications are rare, but it’s pregnant people without prior immunity, the immunocompromised, and those with certain blood disorders that are at greater risk of complications, so just keep your sick kids away from others.
There is no vaccine but antibodies from prior infections are thought to protect from reinfection.
Next up: The flu.
Each year, it causes tens of millions of people to get sick, sends hundreds of thousands to the hospital, and kills tens of thousands.
Often times people note that they get the flu vaccine but still get the flu. And it’s true, the goal of current flu vaccines is less about protecting you from getting sick at all (though sometimes it’s good at that) and more about reducing your risk of serious illness, which it is good at!
In seasons where the flu vaccine is well matched to circulating strains, it’s estimated to reduce your risk of needing to seek medical care by 40-60%.
Something cool about the annual flu vaccine this year: for the last 10 flu seasons, the flu vaccine has been
This means it included coverage for 4 types of the flu: two types of influenza A and two types of influenza B.
This year, the vaccines will be trivalent, so it will only include coverage for 3 types of flu
This is because one lineage, the flu B/Yamagata strain, hasn’t been seen anywhere since March of 2020.
COVID mitigation strategies of masking and physical distancing effectively eliminated a whole strain of the flu!
While flu vaccines work pretty well, we’re always striving for something better.
There are a number of animal studies (which are the first step in scientific progress) that have shown positive results in attempting to make a flu vaccine that covers more strains of the flu and only has to be given as a nasal spray.
The ultimate goal will be a long-lasting vaccine for flu, think every five to 10 years, and that’s being worked on from a number of creative angles.
And I should know. Just yesterday I got out of the hospital after nine days volunteering in a flu challenge study. But we’ll talk about that more in an upcoming episode….
Respiratory syncytial virus, AKA RSV, is another heavy hitter in the winter, and it’s the riskiest for infants and adults over 60.
In infants, it’s the leading cause of hospitalization. But there are multiple options for how to protect this group.
One option is a vaccine by Pfizer that’s given to pregnant people who are between weeks 32-36 of pregnancy and will be delivered during RSV season, which runs from about September to January.
The antibodies produced by this vaccine are passed down to the baby during delivery and studies showed it reduced the risk of severe RSV disease by 70-80% in the first 6 months of life.
Another option is monoclonal antibodies.
Vaccines train your immune system to respond to a pathogen by building up antibodies over a period of time, but monoclonal antibodies (or mAbs for short) just give you pre-made antibodies that are ready to go.
The mAbs for RSV in infants are approved for infants 8 months or younger who will either be born during the RSV season or entering their first RSV season.
The data from the first RSV season for which the mAbs were available showed it reduced the risk of hospitalization by 90%.
Exclusive breastfeeding has also been associated with a reduction in the risk of severe RSV, but the mechanism by which that works isn’t completely clear.
For adults over 60, there are two vaccines that have been approved. During the 2023-2024 season, one dose of either vaccine was found to be about 70-80% effective at reducing the risk of RSV associated hospitalization or emergency room visits.
Pretty good when you consider it’s estimated to be responsible for 6,000-10,000 deaths a year in this age group.
Human metapneumovirus, human parainfluenza, adenovirus, rhinovirus, and non-polio enterovirus are all additional respiratory viruses that are fairly similar.
None have any specific antiviral treatments. None have vaccines.
Mostly I want to bring these up because so often I hear people say, “I have these symptoms but my COVID test was negative.”
There’s a lot of other stuff out there that can make you sick! If you have symptoms but a negative COVID test you still need to stay home!
Finally, we need to talk about norovirus.
Ok fine, norovirus isn’t actually a respiratory virus. It’s a gastrointestinal virus, but its misnomer nickname is “the stomach flu” (even though it’s not related to influenza), and it has the highest incidence from November to April.
Most people can recover in one to three days with fluid replacement (don’t get dehydrated), but it can still be contagious for up to two weeks.
People shed large amounts of the virus in their stool and vomit and others get sick by coming into close contact with the virus through caring for others, touching contaminated surfaces, or eating or drinking contaminated foods.
And it can live on surfaces for up to two weeks. So, make sure to decontaminate all areas that may have been exposed to fluids.
