In the US, there are 3 vaccines that are being used: The Pfizer-BioNtech vaccine (brand name: Comirnaty), Moderna vaccine (Spikevax), J&J's vaccine (Janssen COVID-19 vaccine – Yes! that's the name!). Amongst the three, Janssen is least used because of hesitance due to the very very very remote possibility of TTS (TTS = Thrombosis with Thrombocytopenia Syndrome – another day about TTS). Regardless, what do we know about side effects and if they can be different in males vs. females? Well, as with many other things in life, there does seem to be sex-specific differences in side effects experienced after vaccination. Based on published studies and general reporting in the Vaccine Adverse Event Reporting System (VAERS), this is what we know:
Women are at greater risk for the following adverse and serious adverse events:
- Nausea and vomiting; erythema, local pain and swelling, headache, diarrhea
- Anaphylaxis and TTS (Note the risks are – as I mention above – very very very low, waaaay lower than the risk of being infected with covid and suffering from long haul symptoms)
Men, on the other hand, are at greater risk for the following adverse and serious adverse events:
- Fever, fatigue, lymphadenopathy, facial paralysis, myalgia
- Myocarditis and pericarditis (again, quite rare and when occurs it has been observed only in adolescents and men under 30 years)
So, why are women predisposed to certain adverse events more than men? Well there seems to be some biological and some behavioral reasons: For example, women are more open to reporting adverse events than men. Women also tend to generally have a stronger immune response, likely associated with hormones – eg. testosterone causes a weaker immune response vs. estrogen and progesterone that apparently boost immune response (all of which is good, unless when it is a side effect of a vaccine or being more prone to autoimmune conditions). Also how the two sexes perceive pain and unpleasant stimuli are quite different. And finally, it is also suggested that clinical trials usually account for body mass of men, which typically is bulkier than women – which could mean that women get more dose when jabbed than the men.
Anyways, the point is – do not be surprised if your male or female friend or male and female child report very different symptoms from one another. Thinking back can you remember if there were male-female differences in side effects following covid19 vaccination?
Be well,
Dr. Vani
BTW, Comirnaty??? If you fancy, call it by its non-proprietary name, Tozinameran. But what's in a name? Well, not quite what Juliet thinks!