Not Eligible for a Covid Booster Shot? Here’s Why!

Betty Chaffee/ October 6, 2021/ Coronavirus, COVID-19, immunization/ 7 comments

In our last blog post, we explained the newest CDC guidelines for Covid-19 booster shots. Just a quick recap - it is only for those who received the Pfizer/BioNTech vaccine, and only certain groups of people were made eligible. Since then, I've heard a lot of questions from people about why they aren't eligible for a booster. I've even heard from some who've found a way to get one even though they're not technically eligible. So I want to explain the CDC's reasoning for who's eligible, and for limiting their decision to the Pfizer/BioNTech vaccine.

Why only Pfizer/BioNTech?

The committee that advises the CDC reviewed a lot of data regarding the immunity provided by the Covid-19 vaccines. It was clear to them that immunity wanes over time. But when they looked more closely, it turned out that immunity clearly dropped off only for those who got the Pfizer/BioNTech vaccine. Waning of immunity wasn't so clear for those who got the Moderna vaccine. In fact, a publication from the CDC last month suggests that the Moderna vaccine may actually provide more lasting protection than either of the other vaccines. And because the Janssen vaccine came later and has been given much less often, there's not enough information yet to assess.

So for now, we know that immunity from the Pfizer vaccine wanes, the Moderna vaccine continues to protect, and we don't know enough yet about Janssen.

Why target only older adults?

Information clearly showed that immunity to the Pfizer vaccine wanes over time. But the waning was most pronounced in those who were 65 and older. Younger people still had pretty good protection from all three vaccines, even after several months. So it's the older folks who are more likely to lose some of the initial immunity.

What about those who are 50 and older with health problems?

If you're fully vaccinated, your chances of having a breakthrough case of Covid-19 is low. But we know it happens. And if you're 50 or older with chronic health problems, your risk of getting really sick if you do get Covid-19 is still quite high. If you're in this group, the CDC says you should get a booster.

Then there are the "maybe's".

If you're 18-49, the CDC says you may be a candidate for a booster. There are two reasons behind that. First, chronic health problems can significantly increase your risk of hospitalization and death from Covid-19. Second, if you live or work in a high-risk situation, you may be exposed to Covid-19 often and likely to become ill. If you're in this group, CDC recommends talking your healthcare provider about your individual risks and benefits of getting a booster (read on for information about risks).

Then there are all the others who were "left out".

You're under 50, no concerning health problems, not at high risk of exposure to Covid-19. Or you're any age, and happened to get the Moderna or Janssen vaccine. You may feel like you were left out of the chance to get a booster shot. But for you, CDC can't justify the possible risks of getting a booster shot when the expected benefits are relatively low.

Wait, what? Haven't we always said that the risks of the Covid vaccine are really low compared to the benefits? It's true that even here at BetterMyMeds, we've been saying all along that the risks of the Covid vaccine are low, and the benefits far outweigh those risks. What's up?

Why are we suddenly worried about the risks of this vaccine?

Well, first, let me say that public health experts, including the CDC, have always had an eye on the risks of Covid vaccines. Early on, few vaccine risks were known, but the benefits were tremendous. As the vaccines became widely distributed, we slowly learned about concerning adverse effects. Severe allergic reactions, blood clots, Guillain Barre syndrome, myocarditis and pericarditis. But they occurred quite rarely. So when we were talking about getting everyone their initial vaccines, it was clear that the benefits still outweighed the risks in almost everyone.

But now we're talking about a booster dose. And there's very little information available about adverse effects from a booster, since relatively few people have gotten one so far. Will the adverse effects be the same? So far, that appears to be the case. But we've all learned that when something is given to not just a hundred people, but millions, that picture can change. Will the frequency of adverse reactions increase? Will new adverse reactions be seen?

Bottom line, the actual risks of a booster shot aren't known yet with any certainty. And so public health experts can't say for sure that the risks are low. If you're in one of the "left out" groups, the experts are saying that the benefit of getting a booster is low, and the risks aren't clear. So they're not confident that the benefits outweigh the risks for you. 

Balancing benefits and risks

When I'm asked about the booster, my answer is always to trust the experts. Follow their guidance. They spent a lot of time poring over information to make decisions that are safe and effective for the public. If the experts say to wait until more information comes in, let's wait.

Public health experts are currently saying there are clear benefits to boosters for those who are 65 and older. Same for people living in long-term care facilities, or who are over 50 with chronic health problems. They understand there are risks, too, but are confident that the benefits of the extra shot far outweigh those risks.

If you're 18-49, and you live or work in a risky environment, or have chronic health problems, you and your healthcare provider should look carefully at the risks of a booster (which are not yet clear) and balance them against the benefit it might provide.

If you're 18-49, healthy, not at high risk of exposure, or got the Moderna or Janssen vaccine, you're not likely to benefit from a booster.  And we know there are rare, but real, risks of adverse events. If you've considered trying to get one anyway, I suggest being patient. Trust the experts. Wait for more information to come in. We'll know more soon enough, about both the risks and benefits of Covid vaccine boosters.

As always, we welcome your comments and questions in the space below. Or you can contact us directly at BetterMyMeds. We love hearing from you!







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About Betty Chaffee

Betty Chaffee, PharmD, is owner and sole proprietor of BetterMyMeds, a Medication Management service devoted to helping people get the maximum benefit from their medications.


  1. One thing that scares me about “Trust the experts”, is that I recently heard that doctors are supposed to inform the FDA when patients develop side effects to a drug that the doctor prescribed. It was stated that doctors are only reporting in less than 1% of cases. I get the feeling that the FDA does not know the true effects of drugs. There’s supposed to be a system for reporting on vaccine side effects but I feel the doctors may be holding out

    1. That’s a good point, Tony.

      The only way to know about side effects from drugs and other treatments is if they get reported. And it’s true that for vaccines, health professionals are required to report possible adverse effects through the VAERS system. It’s a passive system though, meaning it relies on individuals to complete and submit a report. But it’s not just health professionals that can and should report possible problems. Patients can do it too, through the same system. So we’re all responsible for getting information into the hands of those who can analyze it and determine its importance.

      The V-Safe program that was launched with the Covid-19 vaccines was a great step in the right direction. That delivers a short questionaire to your cell phone asking about side effects you’ve experienced (or not) along with whether you come down with Covid-19 after getting vaccinated. It’s a step above “passive” because you get a text and you have to either deal with it or delete it — it reminds you to report. And it doesn’t rely on anyone but you to do it. A pretty cool idea, I think.

      And just so you know, there’s also a reporting systme for other drugs and medical therapies. Anyone can report a possible problem through the Med Watch reporting system.

  2. Thanks Betty. I agree that the V-Safe is a good thing. I wasn’t aware of MedWatch. I have not needed a prescription drug in a long time but think that program should be included in the packaging of all drugs. Is it included these days? The print is so fine that I cannot read it without magnification. I would probably not even try to read it anyway.

    1. Honestly Tony, I’m not sure. Since my pharmacy practice doesn’t include actually filling and dispensing prescriptions, I don’t get a chance to see those pamphlets. I’d be surprised if there was a mention of MedWatch. I’ll see if I can get Alan Tanabe to weigh in on this one.

    2. Excellent question, Tony!
      Yes, prescription drug information sheets do mention MedWatch. The following information in required to be included on these handouts:
      “You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at”

      Additionally, if you find the print to be too fine for you to read, I believe most pharmacies have the ability to provide patient with copies of drug information sheets with larger print.

      1. Thanks for that information Alan!

      2. Thanks to both of you. I share your posts on the only social media site that I’m on, Facebook. Your information is helpful.

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