What Should You Know About Vaccine Effectiveness?

At one time, vaccines were not very controversial. In the 1950s, parents were overjoyed to vaccinate their children against polio. I should know. My parents feared I would die because I caught polio when I was a child. I spent weeks immobilized in traction in a polio ward. That was in 1947 and 1948, before there was a polio vaccine. Children were dying all around me of a disease that could not be cured. That experience left lasting scars. That’s why I care a lot about vaccine effectiveness. What do you need to know about various vaccines and how well they work?

How Good Is Influenza Vaccine Effectiveness?

We are still dealing with an influenza outbreak in the Northern Hemisphere. The CDC reported on February 6, 2026 that:

• “Seasonal influenza activity remains elevated nationally.
• “Influenza A activity is decreasing while influenza B activity is increasing nationally and in most areas of the country
• “The weekly influenza-associated hospitalization rate overall in FluSurv-Net peaked during Week 52 at 12.8 per 100,000 population. This is the second highest peak weekly rate overall since the 2010-2011 season.
• “CDC estimates that there have been at least 22,000,000 illnesses, 280,000 hospitalizations, and 12,000 deaths from flu so far this season.”

The FDA has not yet released preliminary data on influenza vaccine effectiveness for the 2025-2026 flu season. Canada is ahead of us, though.

The Center for Infectious Disease Research and Policy (CIDRAP, February 6, 2026) reports that:

“The effectiveness of this season’s flu vaccine in Canada is 40% against medically attended infection with influenza A(H3N2) viruses, 37% against newly emerged and predominant subclade K of the H3N2 strain, and 31% against the H1N1 influenza A strain, an interim analysis estimates.”

That is about typical when it comes to vaccine effectiveness.

Do you find an overall flu vaccine effectiveness rate of 40% disappointing? We do. Here are the CDC numbers upon which we base that calculation:

Vaccine Effectiveness in Past Years:

2004-2005: Vaccine Effectiveness was: 10%
2005-2006: Vaccine Effectiveness was: 21%
2006-2007: Vaccine Effectiveness was: 52%
2007-2008: Vaccine Effectiveness was: 37%
2008-2009: Vaccine Effectiveness was: 41%
2009-2010: Vaccine Effectiveness was: 56%
2010-2011: Vaccine Effectiveness was:  60%
2011-2012: Vaccine Effectiveness was:  47%
2012-2013: Vaccine Effectiveness was: 49%
2013-2014: Vaccine Effectiveness was: 52%
2014-2015: Vaccine Effectiveness was: 19%
2015-2016: Vaccine Effectiveness was: 47%
2016-2017: Vaccine Effectiveness was: 42%
2017-2018: Vaccine Effectiveness was: 38%
2018-2019: Vaccine Effectiveness was: 29%
2019-2020: Vaccine Effectiveness was: 39%
2020-2021: Vaccine Effectiveness was not calculated, in part because there was so little influenza.
2021-2022: Vaccine Effectiveness was: 16%
2022-2023: Vaccine Effectiveness was 46%
2023-2024: Vaccine Effectiveness was 49%
2024-2025: Vaccine Effectiveness was 45%

Overall Effectiveness (not including 2021-2022):             39.75%

Some people may find 40% a reassuring number. We’re not overly impressed. This year’s influenza vaccine appears to be about typical if you believe the latest numbers from Canada: 31%-40% effective against this year’s influenza viruses. On the other hand, some protection may be better than no protection.

Why “Just the Flu” Is Not Reassuring:

This reader believes an annual vaccine has protected her!

Q. I just read your article on the possible consequences of “just the flu” and the effectiveness of antivirals. Someone with whom I volunteer had to leave the venue early last night feeling unwell. She reported this morning that her symptoms are consistent with the flu, so I am sharing your information with her. Thankfully, I haven’t had the flu since I started getting an annual vaccine over 30 years ago, but I’m glad to know my options if I do.

A. There are now rapid flu tests available without a prescription in most pharmacies. Having such a test kit on hand is advisable.

We make no recommendations about particular tests, but here are some options:

• iHealth COVID-19, Flu A&B 3-in1 Antigen Rapid Test  

• OSOM Covid Flu Test Combo – 3-in-1 Rapid Flu A B and Covid Home Test Kit

• CorDx TyFast 10 Mins Flu A/B & Covid 19 Multiplex Rapid Test

The People’s Pharmacy is reader supported. When you buy through links in this post, we may earn a small affiliate commission (at no cost to you).

There are several antiviral medications such as oseltamivir (Tamiflu) and baloxavir (Xofluza) that can reduce influenza severity and modestly shorten the duration of the flu. To learn more about ways to combat respiratory infection, you may appreciate our eGuide to Colds, Coughs & the Flu helpful. This online resource can be found under the Health eGuides tab at www.PeoplesPharmacy.com. In it you will learn more about calming coughs naturally and utilizing antiviral medicines against influenza.

Polio Vaccine Effectiveness:

Very few Americans have a clue what polio was like. That’s because this killer virus disappeared from the United States in 1979.

Children get three doses of the polio vaccine before the age of two. A booster is administered between ages 4-6 years. That provides 99% to 100% vaccine effectiveness.

Parents no longer have to watch children die from paralysis. Kids are no longer locked in iron lungs to help them breathe. They don’t have to wear braces on their legs to help them walk. Trust me when I tell you that polio caused panic every summer when it emerged with a vengeance.

Does anyone want to see a return of this dread disease? Of course not! The inactivated polio vaccine (IPV) has pretty much eliminated this scourge from the planet, though there are still a few countries where it lingers: Pakistan, Afghanistan and Nigeria.

Smallpox Vaccine Effectiveness:

Smallpox existed on the planet for thousands of years. This disease caused untold misery and death. It is estimated that 30% of the people who caught the “pox” died. The survivors were often left with horrific scars. Some of them were blind as a consequence of the infection.

We have no way of knowing how many people died from smallpox. In the last century alone, hundreds of millions of people were lost to this virus.

A vaccine actually helped eradicate smallpox from the face of the earth. It is 95% effective in preventing infection. Thanks to this vaccination, smallpox disappeared from the US in 1972. That’s when children here stopped getting vaccinated. The last case identified in the world was in 1977 in Somalia, thanks to a coordinated worldwide vaccination effort.

What About Tetanus?

Tetanus is a potentially life-threatening disease caused by Clostridium tetani. People can get the spores through exposure to contaminated soil or a puncture wound. The classic example is stepping on a rusty nail.

Without immunization, the result can be “lockjaw.” This involves involuntary muscle spasms in the jaw, stomach or other muscles. People have trouble swallowing and can develop seizures or die. There is no cure for tetanus, but the vaccination is roughly 100% effective according to Johns Hopkins Medicine (Sept. 3, 2021).

What About Whooping Cough (Pertussis)?

Once I recovered from polio, my parents were always on alert for any other serious infection. But vigilance did not protect me from whooping cough. It too is a childhood killer.

The bacterium that causes this potentially fatal respiratory disease is Bordetella pertussis. The cough is very distinctive, and it freaked my parents out. They were afraid that they would lose me to whooping cough after I survived polio.

I did manage to overcome this disease, but it left me with a twitchy respiratory tract. Every time I started coughing as a child, my parents would look anxious.

The pertussis vaccine is usually administered with both a diphtheria and tetanus shot. The DTaP vaccines do not provide 100% protection against these diseases, but they do provide 80 to 90% vaccine effectiveness.

Measles, mumps and German measles (rubella) once caused a lot of childhood illness, sometimes with serious complications. For decades, though, most children were vaccinated against these three viral infections without a great deal of controversy. That has changed in recent years, in part due to anti-vaccination campaigns.

What About Vaccine Complications?

Vaccines are not without side effects. We are as concerned about adverse reactions from vaccinations as we are about any medication.

The flu shot can cause some people to feel ill for days. Readers of our column have reported lasting shoulder pain, especially if the shot is not administered correctly. Read about this complication at this link.

The mRNA COVID vaccines have also triggered a range of reactions. Some people report tinnitus (ringing in the ears), headache, muscle and joint pain, fever and fatigue. In rare cases, young men have developed inflammation of the heart muscle. There are also other complications of the various COVID vaccinations. The vaccines are not risk-free by any means.

Vaccines vs. Drug Side Effects:

All drugs have the potential to cause some side effects in some people. That is a fact of life. There are always trade-offs. If you watch any television, you know that prescription drug commercials describe some amazingly horrible adverse reactions.

Here, for example, is a warning that comes with a drug for rheumatoid arthritis called Rinvoq:

“Rinvoq can lower your ability to fight infections, including tuberculosis. Serious infections and blood clots, sometimes fatal, have occurred, as have certain cancers, including lymphoma, and tears in the stomach or intestines and changes in lab results.”

FDA has also announced that drugs in this class (JAK or Janus Kinase inhibitors) can cause:

“…an increased risk of serious heart-related events such as heart attack or stroke, cancer, blood clots, and death.”

This is just one example of medications that can cause life-threatening adverse reactions. It is not meant in any way to diminish the serious side effects of vaccinations. It is just a reminder that there are benefits and risks to every medicine and procedure.

Final Words About Vaccine Effectiveness:

We wish that vaccinations had not become politicized. We would also appreciate more transparency about the effectiveness and the side effects of all vaccines. That way people will be more capable of determining for themselves when a vaccine, like the flu shot, makes sense.

What do you think? I would like to get your opinion about polio, whooping cough, smallpox or tetanus. If there were a Lyme vaccine, would you consider it? How about an mRNA influenza vaccine that was 95% effective? Would you consider it?

If you had crippling rheumatoid arthritis that prevented you from doing the things you love, would you consider drugs like Humira, Enbrel or Rinvoq, even if such drugs have potentially serious side effects? How do you weigh benefits vs. risks?

A small favor please. Google has made it virtually impossible for people to find our articles on the web. If you find our independent voice worthwhile, please send this article to friends and family via email, Twitter or Facebook. There are icons at the top of the page to make it easy.

You can also encourage your contacts to consider subscribing to our FREE electronic newsletter. When people subscribe they get expanded versions of our syndicated newspaper columns and free access to our public radio show via our weekly podcast. Here is a link to help people subscribe. Thank you for supporting our work.

* * *

Joe Graedon is a pharmacologist and was a…

• Founding member of the Society for Participatory Medicine
• Co-editor of the Journal of Participatory Medicine
• Founding member of Patient Advocacy Council and member of the Patient Safety and Clinical Quality Committee of the Duke University Health System from 2003 to 2011
• Doctor of Humane Letters Honoris Causa from Long Island University in 2006 as “one of the country’s leading drug experts for the consumer”
• Fellow in Pharmaceutical Sciences of the American Association for the Advancement of Science (AAAS) for “exceptional contribution to the communication of the rational use of pharmaceutical products and an understanding of health issues to the public” in 2005

Awards: