What’s the latest on second Covid vaccine boosters and should I recommend them to my adult patients?

On March 29, 2022, the CDC and the FDA approved second booster shots of Pfizer and Moderna Covid vaccines for everyone 50 years of age or older as well as people 12 years of age or older with moderate to severe immune deficiencies to be given at least 4 months following the first booster.1-3  This means a 4th dose of an mRNA vaccine for many adults and a 5th dose for those with moderate to severe immune deficiencies. 

Admittedly, these recommendations are made in the context of many uncertainties, including when the next Covid surge will arrive, what will be the predominant variant, and how will our immunity hold up if a surge occurs. 

Nevertheless, in discussing the merits of a 2nd booster, I would emphasize several “talking points”:

  • Covid hasn’t gone away with new cases still diagnosed daily, some still  requiring hospitalization, albeit at lower frequency than recent past. 
  • Our immunity against Covid wanes in the absence of boosters or natural infection.
  • SARS-CoV-2 has been unpredictable in its surges, as well as emergence of new variants with frequent changes in its virulence and ease of transmission. This means we don’t know when the next surge will hit us (summer, fall or later) and how the predominant variant will behave.
  • But let’s not get too hung up on surges! The fact is that as long as Covid is circulating around, maintaining a robust immunity against infection is the best way to avoid getting infected and the best way to do this is through boosters!
  • As more people go around without masks, the risk of unprotected exposure to SARS-CoV-2 is also likely to increase, particularly in indoor public gatherings.  Boosters may allow us the freedom to go maskless more often!
  • The risk of Long Covid even following mild infection is still real even between surges. This means even if we don’t get very sick from Covid, we are placing ourselves at risk of Long Covid. Remember, no Covid, no Long Covid!
  • Irrespective of whether it’s mild or even asymptomatic, Covid infection  can cause significant disruption in our lives, whether it be isolation at home, not being allowed to return to work or just the anxiety of having it or having passed it to others. This means that, at least currently, it’s premature to consider this virus as “just another respiratory virus.”  It’s impact on our everyday lives is still a lot different than typical respiratory viruses. 
  • mRNA vaccine boosters have been proven to be as safe as primary series. 
  • Last, but not the least, a preprint Israeli study involving volunteers 60 to 100 years old found a 78% reduction in mortality from Covid following a 2nd booster dose of Pfizer mRNA vaccine compared to those who only had 1 booster.This study has several limitations including self-selected volunteers who may already be at lower risk of Covid mortality due to their healthier lifestyle. Nevertheless, the data is very encouraging!

Ultimately, the decision to get a second booster, particularly during non-surge periods, will depend a lot on not only available facts but the individual’s threshold for acceptable risk of even mild disease, concern over transmission to others and more recently the cost of the vaccine, among other factors.  

Bonus Pearl: Did you know that each year there are plenty of uncertainties around which influenza A or B subtypes will be the predominant seasonal strain or what month they may surge but these questions never keep us from recommending the annual flu vaccine to the public as a means of reducing influenza cases and saving lives?   

 

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References

  1. D.A. Allows Second Covid Boosters for Everyone 50 and Older – The New York Times (nytimes.com)
  2. Coronavirus (COVID-19) Update: FDA Authorizes Second Booster Dose of Two COVID-19 Vaccines for Older and Immunocompromised Individuals | FDA
  3. CDC Recommends Additional Boosters for Certain Individuals | CDC Online Newsroom | CDC
  4. Arbel R, Sergienko R, Friger M, et al. Second booster vaccine and Covid-19 mortality in adults 60-100 years old. Preprint, posted March 24, 2022. 24514bba-2c9d-4add-9d8f-321f610ed199.pdf (researchsquare.com)

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!

 

What’s the latest on second Covid vaccine boosters and should I recommend them to my adult patients?

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

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?

My middle-age immunocompromised patient receiving immunosuppressants has had 3 doses of mRNA Covid vaccine and is now 4 months out from her 3rd dose.  Should she consider a fourth dose of Covid vaccine?

Yes! According to the Centers for Disease Control and Prevention (CDC) of the U.S.,1 persons who are “moderately or severely immunocompromised” and have received 3 doses of an mRNA vaccine (either Pfizer [12+ years old) or Moderna (18+ years old]) should receive a 4th dose (“booster”) at least 3 months after the 3rd dose.  Similarly, those who initially received a J&J vaccine followed by one of the aforementioned mRNA vaccines and are at least 2 months from the 2nd dose should also receive a 3rd dose (booster. 

The following are considered moderately or severely immunocompromised conditions by CDC: 

  • Active cancer treatment for tumors or cancers of the blood
  • Organ transplant with immunosuppressants on board
  • Stem cell transplant within the last 2 years or taking immunosuppressants
  • Moderate or severe primary immunodeficiency (eg, DiGeorge or Wiskott-Aldrich syndromes)
  • Advanced or untreated HIV infection
  • Active treatment with high-dose corticosteroids or other immunosuppressants

A published study2 of Covid-19-associated emergency department (ED) and urgent care (UC) encounters and hospitalization among adults during a period including Omicron variant predominance in 10 states found vaccine effectiveness for ED/UC visits dropping to 66% and for hospitalization to 78% by the 4th month after a 3rd dose (vs 87% and 91%, respectively during the 2 months after a 3rd dose).  This study did not distinguish immunocompromised from non-immunocompromised persons, however.  More data on the vaccine effectiveness in non-immunocompromised persons at high risk of Covid-19 related complications would be welcome.

Bonus Pearl: Did you know that of American adults who are fully vaccinated against Covid-19, only about 30% have received an additional Covid vaccine dose beyond the primary series3 

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References

  1. Covid-19 vaccines for moderately or severely immunocompromised people (Updated Feb 17, 2022). Accessed Feb 21, 2022.  https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/immuno.html?s_cid=10483:immunocompromised%20and%20covid%20vaccine:sem.ga:p:RG:GM:gen:PTN:FY21
  2. Waning 2-doe and 3-dose effectiveness of mRNA vaccines against Covid-10-associated emergency department and urgent care encounters and hospitalizations among adults during periods of delta and omicron variant predominance—Vision Network, 10 states, August 2021-January 2022. MMWR 2022; 71:255-63. https://www.cdc.gov/mmwr/volumes/71/wr/mm7107e2.htm?s_cid=mm7107e2_w
  3. Hubler S, Harman A. As Cov id surges, experts say U.S. booster effort is falling behind. NY Times, December 18, 2021. https://www.nytimes.com/2021/12/18/us/omicron-booster-shots-americans.html

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!

My middle-age immunocompromised patient receiving immunosuppressants has had 3 doses of mRNA Covid vaccine and is now 4 months out from her 3rd dose.  Should she consider a fourth dose of Covid vaccine?

What’s the evidence that a third dose of mRNA Covid-19 vaccine reduces risk of Covid-19 disease?

The strongest evidence to date demonstrating the effectiveness of a third dose of mRNA Covid-19 vaccine comes from an observational study from Israel which reported 93% effectiveness for admission to hospital, 92% for severe disease and 81% for Covid-19 related deaths when compared to those who had received 2 doses of the vaccine (Pfizer, BNT162b2 mRNA) at least 5 months before.1

This was a large population-based study involving over a million people 16 years or older (one-half in each group) who were eligible for the third dose (median age 52 y); those living in long-term facilities, healthcare workers and those medically confined to their homes were excluded. Vaccine effectiveness was evaluated at least 7 days after receipt of the third dose.  Median follow-up period was 13 days for both groups.

Overall effectiveness of the third dose vs 2 vaccine doses was 93% (88-97) for admission to hospital, 92% (82-97) for severe disease and 81% for death (59-97). Effectiveness of the third dose was similar between males and females and between individuals 40-60 years and those at least 70 years of age; effectiveness could not be determined in the younger age group due to small number of adverse outcomes.

What makes this study stand out among the previous works2,3 is that it controlled for important possible confounders, including sociodemographic factors, clinical factors, and behavioral factors related to Covid-19.  Limitations include its observational nature and exclusion of certain at risk groups, such as nursing home residents and healthcare workers.

Given the increasing number of Covid-19 cases in many communities at this writing, the news that a booster shot of an mRNA vaccine provides further protection in preventing Covid-19 is very welcome!

Bonus Pearl: Did you know that in a study measuring the immune response after the third dose of an mRNA vaccine (Moderna) in those 60 years of age or older, the median antibody titer rose 50-fold!4

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References

  1. Barda N, Dagan N, Cohen C, et al. Effectiveness of a third dose of the BNT162b2 mRNA Covid-19 vaccine for preventing severe outcomes in Israel: an observational study. Lancet, published online October 29, 2021. https://www.thelancet.com/action/showPdf?pii=S0140-6736%2821%2902249-2
  2. Bar-On YM, Goldberg Y, Mandel M, et al. Protection of BNT162b2 vaccine.N Engl J Med 2021; published online Sept 15, https://doi.org/10.1056/nejmoa21114255.
  3. Patalon T, Gazit S, Pitzer VE, et al. Short term reduction in the odds of testing positive for SARS-CoV-2; a comparison between two doses and three doses of the BNT162b2 vaccine. medRxive 2021;published online Aug 31. https://doi.org/10.1101/2021.008.29.21262792 (preprint).
  4.  Eliakim-Raz N, Liebovici-Weisman Y, Stemmer A, et al. Antibody titers before and aftera third dose of SARS-CoV-2 BNT162b2 vaccine in adults ages ≥60 years. JAMA. Published online November 5, 2021. doi:10.1001/jama.2021.19885 https://jamanetwork.com/journals/jama/fullarticle/2786096

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!

What’s the evidence that a third dose of mRNA Covid-19 vaccine reduces risk of Covid-19 disease?