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Ask the Pharmacist: Should I be concerned about getting five different doses of COVID-19 vaccines within a 12-month period?

This content was current as of the date it was released. In science and medicine, information is constantly changing and may become out-of-date as new data emerge.


My oncologist is a CLL specialist and just recommended that I “start over” with COVID vaccines, as two Moderna doses plus the booster have shown no antibody production. Should I be concerned about getting 5 doses of vaccines within a 12-month period? He says I should get two doses of Pfizer and hold my acalabrutinib for 10 days, three days before, and 7 days after.

Answer: It sounds like your CLL specialist gave you some solid advice. We have heard reports of many others doing the same. There is a lot of data available on the safety of the three-shot series of the COVID-19 (mRNA) vaccines, and as you know three shots were recommended early on by the CDC/FDA for the immunocompromised in early fall. Also, both the FDA/CDC now support the mix/match approach and there are even some data indicating an increased immune response can occur as a result of this practice.

We are unaware of any safety concerns. The mRNA components are only present long enough to (hopefully) trigger your body to make an immune response. The materials are then broken down and excreted from our bodies within a few days after vaccination. So, there is no issue surrounding having an excess or build-up of the components in your body all at once. That being said, there are no data yet on five doses that we are aware of, although a couple of other countries have studies that are underway. While it is not the exact same scenario, you have probably heard periodic reports of patients accidentally receiving “too much of a vaccine dose” at one time or another throughout the pandemic. In each of those cases, there were no additional side effects or adverse reactions any more so than the normal expected ones.

Since you are being seen by a CLL specialist, you trust his guidance, AND you have had no response to the vaccine previously, it would definitely be worth another go-around. The risk of contracting COVID-19 while having CLL is known.

Even if you do not mount a response with the additional dosing, please don’t give up hope. Keep an eye on our website regarding the long-acting COVID-19 monoclonal antibody AZD7442 that has been submitted to the FDA for EUA (but not yet approved). As soon as we hear anything new about it, we will be sharing out information as we find out about it. This long-acting antibody, if approved, could be a game-changer for those like you who have been able to mount a response to the COVID-19 vaccine. And of course, make sure you have filled out your COVID-19 Action Plan Checklists which can be found here: