The flu season usually begins to subside by February. Not this year! The US Centers for Disease Control and Prevention say that influenza infections are at the highest rate in 15 years and still rising. Others say it is far worse, more like the terrible outbreak during the1997-1998 influenza attack. Our flu season seemed to peak right around the beginning of January, but instead of fading away, it is rising again now. This influenza outbreak is overwhelming many hospitals around the country.
Some Headlines from Around the Country:
“Our hospital is full to the brim: California overwhelmed by severe flu season” San Francisco Chronicle, Feb. 12, 2025
“Flu is so bad right now that schools across the country are closing” Today, Feb. 6, 2025
“Flu is surging nationwide, with 24 million cases so far” Washington Post, Feb. 10, 2025
“The flu is walloping Mass. in unusual second surge of the season: ‘It’s like a tsunami’” Boston Globe, Feb. 12, 2025
Why Are We So Surprised About This Influenza Outbreak?
If you have been reading our newsletter for awhile, you know that we always look to Australia to predict what our flu season will look like. We do not understand why health professionals don’t follow our lead.
Why check Australia? you ask. Because the southern hemisphere is always 6 months ahead of us. As I write this, the temperature in Sydney is 82° F. Yes, it’s summer in OZ! But several months ago, Australia was in the grip of winter. It was a record-breaking flu season. And the dominant flu strain was influenza A (H3N2).
Australia’s flu season predicted what we are experiencing. The peak in cases came later than usual and lasted longer than in previous years. And guess what: it was the worst flu season since 2019…just what we are now seeing in North America. And the predominant strain? You guessed right: influenza A (H3N2). There is also influenza A H1N1 out there.
Why Is This Influenza Outbreak So Bad?
Under the best of times the CDC data are always a couple of weeks behind what’s actually happening at any given moment. For example, the data we are relying upon to keep you updated come from Feb. 1, 2025. Like other federal health agencies, there have been some hiccups regarding dissemination of health information over the last week or so.
Here is what we do have. About 8 percent of emergency department visits are attributable to influenza. In addition, many people who had the flu back in January are now showing up with complications such as bacterial pneumonia.
According to the CDC, there have been about 24 million cases of influenza so far this winter. We have hit a level of hospitalizations for influenza that are comparable to 2017, which was the highest in recent memory. Here is the most recent CDC map we could get our hands on.
Why Didn’t Flu Shots Protect Us Better Against This Influenza Outbreak?
Some experts blame this year’s bad flu season on vaccine hesitancy. For a variety of reasons, many people have become reluctant to get any vaccines. According to the CDC, vaccine rates are around 44-45% this year. Not great, but not awful either. During the last flu season vaccination rates were about 55% in kids. The trend is down.
There’s another problem with flu shots. They don’t work as well as we think most people would like. I have been tracking influenza vaccination since 2004. Some years the flu shot is 50% to 60% effective. That’s rare. Sometimes it is only 10% to 20% effective. That too is rare. On average, the flu shot is about 40% effective at preventing influenza. You can see how we arrived that that number at this link.
What Should You Know About Vaccine Effectiveness?
It is way too soon to know how effective this year’s flu shot is. But we can look to the southern hemisphere (South America) for some inkling. We are still awaiting data from Australia.
According to the CDC’s MMWR (Octobter 3, 2024):
Adjusted vaccine effectiveness
- 34.5% overall
- 39% among young children
- 32.2% among older adults
So, is the glass half empty or half full? Based on data from South America, the flu shot was a tad less effective than usual, but not dramatically so. If we generalize, we can say that about 1/3 of the people who got a flu shot were able to avoid hospitalization from influenza. That’s good, but it does not tell us how many people caught influenza after getting a flu shot and still felt terrible. Maybe not sick enough to go to the hospital, but still pretty awful.
One other bit of good news is that COVID-19, while still causing infections, is not at a peak. The COVID peak late last summer may have left many people with some immunity. Or perhaps the flu is crowding COVID out for now.
What to Do About This Influenza Outbreak:
If you read our newsletter regularly, you know that I am extremely disappointed in our public health officials. They focus on flu shots as the primary strategy for preventing influenza, even though they know the vaccines are only partially effective.
What they rarely, if ever, mention is air quality. Florence Nightingale was the founder of modern nursing. In the middle of the 19th century, she was crusading for better ventilation in hospitals. We too have been crusading for better air quality in doctor’s offices, dentist’s offices, pharmacies, supermarkets, banks and anywhere that people gather without face masks. You can listen to our podcast on this topic at this link.
Show 1357: Revisiting Ventilation to Avoid Airborne Germs
You can read about HEPA and MERV 13 high-quality air filters at this link.
And if you would like to learn about what you can do to treat the symptoms of influenza if you are unlucky enough to catch it, here is a link to our podcast with Dr. Roger Seheult. Dr. Seheult is quadruple board-certified in Internal Medicine, Pulmonary Diseases, Critical Care Medicine, and Sleep Medicine through the American Board of Internal Medicine. HIs current practice is in Beaumont, California, where he is a critical care physician, pulmonologist, and sleep physician at Optum California. Dr. Seheult describes medical topics better than anyone we know and his practical advice is quite compelling.
You may also find our eGuide to Colds, Coughs & the Flu helpful. It can be found under the Health eGuides tab at this link.
Final Words:
Have you caught the flu this winter? If so, please describe how it went. What did you do to ease your symptoms? If you have so far avoided the influenza outbreak, tell us your secret. How have you managed to dodge this bullet?
And if you found this article helpful, please send it to friends and family. We would be grateful if you encourage them to sign up for our free newsletter at this link.
Citations
- Zeno EE et al, "Interim Effectiveness Estimates of 2024 Southern Hemisphere Influenza Vaccines in Preventing Influenza-Associated Hospitalization — REVELAC-i Network, Five South American Countries, March–July 2024." MMWR, Oct. 3, 2024. https://pubmed.ncbi.nlm.nih.gov/39361525/
