Health Advice



To aspirate or not to aspirate before a shot? Both are OK

By Keith Roach, M.D. on

DEAR DR. ROACH: Would it be reasonable for me to ask the tech to aspirate the plunger when I go for a vaccine? I understand that the veins in the shoulder are rarely accessible to an IM needle, but still, I would not mind the extra 5 to 10 seconds of discomfort while the tech looks to see if blood has appeared because the needle is in a vein. And I have heard it is desirable to keep the COVID vaccine in particular spot. If the tech refuses, do I walk away and try elsewhere? -- R.A.

ANSWER: I was taught to aspirate (that is, pull back on the plunger of the syringe for a second) prior to injecting the vaccine. This is no longer recommended, as there aren't any large veins in the recommended part of the deltoid muscle for a vaccine to be injected, which matches my experience of never seeing a flashback of blood in thousands of injections. There is essentially no benefit to doing the aspiration, so I would recommend you not worry about it.

However, my experience is also that some people still worry, even when I advise them not to, and asking your medical professional to aspirate is fine. It's not dangerous, and if it's worth the peace of mind for a couple of seconds of discomfort, it shouldn't be a problem. You'll want to find someone who was trained in the old technique.

DEAR DR. ROACH: I read in the newspaper that it was discovered that a person's immunity against COVID-19 wanes over time, and that is why they are suggesting booster shots. What test is being used to measure a person's immunity, and how can I test my wife for that? She had both Moderna shots over seven months ago. We had an antigen test done on her, and our doctor said it came back negative.

She had her 19th, and last, Rituximab treatment February 2021. We have tried to get my wife revaccinated and were turned down by two pharmacies. We have a note from her neuro-oncologist strongly recommending the vaccine, but that did not help with the pharmacies. -- D.S.

ANSWER: I am surprised to hear it. At the time of this writing, booster shots are approved for all adults. A note from your wife's doctor should have been adequate explanation for the vaccine.


Rituximab (and similar drugs) is used for some cancers and autoimmune disorders. It works directly on the B-cells, the antibody-producing cells of the immune system. Of all the medicines that interfere with a vaccine, rituximab is probably the most significant, which is why it's best to get the vaccine at least four weeks before starting rituximab if possible. Vaccines given 12 months after completing rituximab were also effective, but not as effective as in people who had never had rituximab. In this pandemic, there is a trade-off between getting the vaccine as soon as possible and waiting for the rituximab effects to dissipate to get the most effect from the booster. I would consider getting one as soon as possible and again six months after the third dose, which would be well after her one-year anniversary in February.


Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to or send mail to 628 Virginia Dr., Orlando, FL 32803.

(c) 2022 North America Syndicate Inc.

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