Adverse events

Should healthy adults receive a Covid vaccine booster shot and why?

FA Manian MD, MPH, , , , , , , , , Leave a comment

A booster shot of Covid vaccine (eg, mRNA, Pfizer or Moderna) is now recommended by the CDC even for healthy adults as follows:1

  • If you received Pfizer vaccine as your primary series, are ≥12 years old and at least 5 months after your 2nd dose
  • If you received Moderna vaccine as your primary series, are ≥18 years old and at least 5 months after your 2nd dose
  • If you received J&J vaccine, are ≥18 years old and at least 2 months after your 1st dose

There are at least 3 reasons for receiving a Covid vaccine booster: 1

  • Waning immunity after primary vaccine series
  • Emergence of Omicron variant which seems to be less responsive to the existing immunity from the vaccine
  • Recent data from clinical trials showing that a booster shot increased the immune response in trial participants who completed an either Pfizer or Moderna mRNA vaccine primary series 6 months earlier or had J&J vaccine single dose 2 months earlier

Here is the data from CDC on the vaccine effectiveness against Covid based on epidemiologic data on emergency department (ED)/urgent care (UC) encounters or hospitalization during the recent Omicron-predominant period:2

 Vaccine effectiveness against ED/Urgent care encounters 

  • 2 doses of mRNA vaccine: 41% (69% <2 months vs 37% ≥5 months after last dose)
  • 3 doses of mRNA vaccine: 83% (87% < 2 months vs 66% 4 months vs 31% ≥5 months)

Vaccine effectiveness against hospitalization 

  • 2 doses of mRNA vaccine: 55% (71% < 2months vs 54% ≥5 months)
  • 3 doses of mRNA overall 88% (91% if < 2 months, 78% if ≥4 months)

So take full advantage of available Covid vaccines and maximize your chance of not getting Covid!

 

Bonus Pearl: Did you know that a recent CDC study found that people 18 years and older who received the same mRNA vaccine brand for all their vaccinations experienced fewer adverse reactions following the booster dose than they did after their second dose of mRNA vaccine, with 92% of reported reactions not considered serious?3

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References

  1. Covid-19 vaccine booster shots. Feb 2, 2022. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/booster-shot.html#:~:text=It%20depends.,after%20the%20J%26J%2FJanssen%20vaccine. Accessed Feb 24, 2022
  2. Waning 2-dose and 3-dose effectiveness of mRNA vaccines against Covid-19-associated emergency department and urgent care encounters and hospitalizations among adults during periods of delta and omicron variant predominance-VISION network, 110 states, August 2021-Jan 2022. Feb 18, 2022 https://www.cdc.gov/mmwr/volumes/71/wr/mm7107e2.htm#T1_down. Accessed Feb 24, 2022.
  3. New CDC studies: Covid-19 boosters remains safe, continue to offer high levels of protection against severe disease over time and during Omicron and delta waves. Feb 11, 2022. https://www.cdc.gov/media/releases/2022/s0211-covid-19-boosters.html. Accessed Feb 24, 2022

 

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Mercy Hospital-St. Louis, Massachusetts General Hospital, Harvard Catalyst, Harvard University, their affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

Should healthy adults receive a Covid vaccine booster shot and why?

Are women at higher risk of Covid-19 vaccine-related adverse events?

FA Manian MD, MPH, , , , , , , , , , , , , , , , , , , , , , , , , Leave a comment

Data to date shows a preponderance of Covid-19 vaccine-related adverse events (AEs) among women compared to men. This finding may be due to the generally more robust immunological response to infections and vaccines among women, increased reporting of AEs by women, genetic factors, microbiome differences as well as other factors.1-3

A CDC study involving mRNA vaccines (Pfizer and Moderna) during the 1st month of vaccination roll out in the US, found that nearly 80% of adverse events were reported by women.  The great majority (>90%) of these AEs were not serious and included symptoms such as headache, dizziness and fatigue.1

A JAMA study involving individuals receiving one of the mRNA vaccines found that 94% (Pfizer) and 100% (Moderna) of anaphylaxis events occurred among women. Of note, the median age was ~40 years  with the majority of anaphylaxis events were reported after the first dose. 2

Higher incidence of AEs following Covid-19 vaccination is not surprising and may be explained biologically. Women typically have a more robust immune response to infections and vaccination, both at the level of innate and adaptive immunity with higher antibody responses.  

These findings may be in part due to hormones such as estrogen which is known to enhance differentiation of dendritic cells and proinflammatory cytokine production. Other proposed mechanisms include differences in microbiome between sexes and sex-based genetic influences on humoral immune profile with the X chromosome expressing 10 times more genes than the Y chromosome, including genes that influence immunity.3

Bonus Pearl: Did you know that anaphylactic reaction to the mRNA Covid-19 vaccines is extremely rare, occurring in only 2-5 cases/ million!2

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Subscribe to Blog via Email

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References

  1. Gee J, Marquez P, Su J, et al. First month of Covid-19 vaccine safety monitoring—United States, December 14, 2020—January 13, 2021. MMWR 2021;70:283-88. https://www.cdc.gov/mmwr/volumes/70/wr/mm7008e3.htm
  2. Shimabukuro TT, Cole M, Su JR. Reports of anaphylaxis after receipt of mRNA Covid-19 vaccines in the US—December 14, 2020-January 18, 2021. JAMA 20201;325:1101-1102. https://jamanetwork.com/journals/jama/fullarticle/2776557
  3. Fischinger S, Boudreau CM, Butler AL, et al. Sex differences in vaccine-induced humoral immunity. Semin Immunopath 2019;41:239-49. https://pubmed.ncbi.nlm.nih.gov/30547182/

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Mercy Hospital-St. Louis or its affiliate healthcare centers, Mass General Hospital, Harvard Medical School or its affiliated institutions. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

Are women at higher risk of Covid-19 vaccine-related adverse events?