How effective are the mRNA Covid-19 vaccines in reducing the risk of hospitalization among adults 65 years of age or older?

The mRNA vaccines by Pfizer and Moderna seem very effective in not only reducing risk of symptomatic Covid-19 but also risk of hospitalization among adults 65 years of age or older.   A CDC study published on April 28, 2021, showed a vaccine efficacy of 94% among fully immunized and 64% among partially immunized adults ≥ 65 years of age  with approximately one-half of subjects  ≥75 years old.1

This study was carried out in 24 hospitals in 14 states in the U.S. during January 1, 2021-March 26, 2021, and involved 417 patients: 187 case-patients with Covid-19 and 230 controls with negative SARS-CoV-2 PCR test.  Among patients with Covid-19, 10% were partially immunized (vs 27% among controls) and 0.5% were fully immunized (vs. 8% among controls). 1

An Israeli study in a nationwide mass vaccination setting involving persons (28% ≥ 60 y) receiving Pfizer mRNA vaccine similarly found a vaccine efficacy of 74% for hospitalization for partially immunized and 87% for fully immunized persons.2

The high effectiveness of mRNA vaccines against more severe Covid-19 requiring hospitalization is great news, of course, as advanced age is by far the greatest risk factor for death from Covid-19, independent of underlying comorbidities.3   

Bonus Pearl: Did you know that prior to the availability of effective Covid-19 vaccination, adults over 65 years of age represented 80% of hospitalizations and had a 23-fold greater risk of death than those under 65?3

Liked this post? Download the app on your smart phone and sign up below to catch future pearls right into your inbox, all for free!

Subscribe to Blog via Email

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

References

  1. Tenforde MW, Olson SM, Self WH, et al. Effectiveness of Pfizer-BioNTech and Moderna vaccines against COVID-19 among hospitalized adults aged ≥65 years-United States, January-March 2021. https://www.cdc.gov/mmwr/volumes/70/wr/mm7018e1.htm?s_cid=mm7018e1_w
  2. Dagan N, Barda N, Kepten E, et al. BNT162b2mRNA Covid-19 vaccine in a nationwide mass vaccination setting. N Engl J Med 2021;384:1412-1423. https://www.nejm.org/doi/10.1056/NEJMoa2101765
  3. Mueller AL, McNamara MS, Sinclair DA. Why does COVID-19 disproportionately affect older people. Aging (Albany NY) 2020;12:9959-9981. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7288963/

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!

How effective are the mRNA Covid-19 vaccines in reducing the risk of hospitalization among adults 65 years of age or older?

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

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

Liked this post? Download the app on your smart phone and sign up below to catch future pearls right into your inbox, all for free!

Subscribe to Blog via Email

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

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?

My elderly patient developed a flare-up of her gout few days after receiving Covid-19 vaccine. Is there a connection between immunization and gout flare?

Although the connection between Covid-19 vaccination and gout flare has yet to be established, higher rates of gout/gout flare following the administration of several other vaccines (eg, influenza, tetatnus, recombinant zoster) have been reported.1  Thus, it is conceivable that Covid-19 vaccine may also be associated with gout flare as more and more people are immunized.  

A 2019 prospective study of over 500 patients with gout found that vaccination was associated with 2-fold higher odds of gout flare (aO.R. 1.99; 95% ci 1.01-3.89) during the 2 day period following immunization; no information on the type of vaccines administered was provided, however.1  Similarly,  higher risk of gout (3.6-fold) has been reported in recipients of recombinant zoster vaccine following immunization.1

An intriguing mechanism explaining the association of vaccination and gout flare is the activation of the Nlrp3 inflammasome, a multiprotein complex produced in response to diverse stimuli such as uric acid crystals and ATP released from tissue injury/necrotic cells.2 Of interest, ~25% of patients with asymptomatic hyperuricemia have been found to have evidence of monosodium urate crystals in and around their joints by advanced imaging, such that vaccination may potentially bring out more inflammatory response and gout flare.

Although aluminum adjuvants intended to increase the immunogenicity of one-half of all routine adult vaccines (eg, tetanus, diphteria, pertussis) have been shown to activate the Nlrp3 inflammasome in vitro, neither currently available mRNA vaccines (Pfizer, Moderna) nor the Johnson&Johnson vaccine contains aluminum as an adjuvant. 4  

Despite the potential for gout flare following adult vaccination, it should be emphasized that the absolute risk is still low and pales compared to the overwhelming benefits of vaccination in general.1

Bonus Pearl: Did you know that, in addition to the usual uric acid lowering drugs, losartan, fenofibrate and some non-steroidal anti-inflammatory drugs, such as indomethacin, also lower serum uric acid levels? 5,6

Liked this post? Download the app on your smart phone and sign up below to catch future pearls right into your inbox, all for free!

Subscribe to Blog via Email

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

References

  1. Yokose C, McCormick N, Chen C, et al. Risk of gout flares after vaccination: a prospective case-crossoverstudy. Ann Rheum Dis 2019;78:1601-1604. https://ard.bmj.com/content/early/2019/07/31/annrheumdis-2019-215724.info?versioned=true
  2. Lyer SS, Pulskens WP, Sadler JJ, et al. Necrotic cells trigger a sterile inflammatory response throught the Nlrp3 inflammasome. PNAS 2009;106:20388-20393. https://pubmed.ncbi.nlm.nih.gov/19918053/
  3. Yokose C, Choi H. Response to “Clarification regarding the statement of the association between the recombinant zoster vaccine (RZV) and gout flares’ by Didierlaurent etal. Ann Rheum Dis Month, December 2019. https://ard.bmj.com/content/annrheumdis/early/2019/12/18/annrheumdis-2019-216670.full.pdf
  4. Covid-19 vaccine information. https://covidvaccine.mo.gov/ Accessed March 16, 2021.
  5. Daskalopoulou SS, Tzovaras V, Mikhailidis DP, et al. Effect on serum uric acid levels of drugs prescribed for indications other than treating hyperuricaemia. Current Pharmaceutical Design 2005;11:4161-75. https://www.eurekaselect.com/60510/article
  6. Tiitinen S, Nissila M, Ruutsalo HM, et al. Effect of nonsteroidal anti-inflammatory drugs on the renal excretion of uric acid. Clin Rheumatol 1983;2:233-6. https://pubmed.ncbi.nlm.nih.gov/6678696/#:~:text=The%20effect%20of%209%20nonsteroidal,studied%20had%20no%20significant%20influence.

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. 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!

My elderly patient developed a flare-up of her gout few days after receiving Covid-19 vaccine. Is there a connection between immunization and gout flare?