covid: mRNA vaccine safe 2nd shot after immediate reaction to 1st

 

a recent multicenter retrospective study conducted by several academic medical centers found that patients given an mRNA vaccine who had an immediate reaction to the first dose tolerated the second dose well (see covid vaccine after immed rxn jama2021 in dropbox or doi:10.1001/jamainternmed.2021.3779)

 

Details:

-- 189 patients had an immediate allergic reaction to an mRNA vaccine, defined as symptom onset within four hours of the first dose, at least one allergic symptom, and referral for an allergy/immunology consultation assessment

-- mean age 43, 86% women, 69% Moderna vaccine/31% Pfizer

-- first dose reactions:

    -- flushing or erythema: 53 people (28%)

    -- dizziness or lightheadedness: 49 people (26%)

    -- body tingling: 46 people (24%)

    -- through tightness 41 people (22%)

    -- hives: 39 people (21%)

    -- wheezing or shortness of breath: 39 people (21%)

    -- anaphylaxis: 17% (32 people)

-- allergist skin testing performed in 80 people (42%) in some of the higher risk patients, none were positive for polyethylene glycol 3350

-- anaphylaxis was as per the Brighton and the National Institute of Allergy and Infectious Diseases/ Food Allergy and Anaphylaxis Network Criteria

        --for the Brighton Collaboration anaphylaxis criteria, see https://www.spsu.ch/en/docs/media/273d46e0-5363-49c4-aec8-a2d190b75acf/4692a94e94a54deabc8acf1136815161

-- dose 2 of the mRNA vaccine was given to 159 patients (84%)

-- 50 patients (31%) received premedication with a non-sedating oral antihistamine (47 of the 50 patients) prior to the second shot

 

Results:

-- immediate allergic symptoms occurred in 32 patients (20%) but all were in a lower severity compared to what happen when the first dose

    -- none required treatment with epinephrine or urgent care/emergency department visits

    -- symptoms included:

        -- tachycardia: 6 people

        -- dizziness/lightheadedness: 6

        -- throat tightness: 6

        -- flushing/erythema: 5

        -- swelling: 4

        -- hives: 3

        -- wheezing/shortness of breath: 3

        -- hypertension: 2

        -- body tingling: 2

        -- nausea/vomiting/abdominal pain: 1

-- of the 32 patients who had first dose anaphylaxis, 19 received and tolerated dose 2 without a problem

 

Commentary:

-- allergic reactions after an mRNA vaccine are not uncommon, reported as up to 2% of individuals with 2.5 per 10,000 having anaphylaxis, per the authors

    -- a report in February suggested that anaphylaxis was actually much less frequent than this: see http://gmodestmedblogs.blogspot.com/2021/02/covid-mrna-vaccine-anaphylaxis-overblown.html

-- in this study 20% of patients did have mild symptoms after the second mRNA dose, but none had significant allergic symptoms.

-- Per these authors, this suggests that many of these initial reactions were not truly allergic reactions to or perhaps were from a non-IgE mediated allergic mechanism

-- the study was important given that it reinforced the ability to give a second dose of an mRNA vaccine to complete the series. The CDC had recommended that individuals with an immediate and potentially allergic reaction to the first dose could receive a Janssen/J& J subsequent vaccine.

    -- Although the immune response to an mRNA vaccine followed by the non-mRNA Janssen vaccine is unclear, there are some concerns raised by a prior study that found that the Pfizer mRNA vaccine followed by the AstraZeneca non-mRNA vaccine did have blunted anti-spike IgG responses (see http://gmodestmedblogs.blogspot.com/2021/07/covid-mixing-and-matching-vaccines.html )

 

Limitations:

-- this was a retrospective analysis of data combined from five different academic medical centers, so there may well have been institutional differences in classifications, treatments and analyses

-- there was not much granular data in the short research letter, so we do not know many potentially useful details:

    -- premedication prior to the second shot varied from 11% in one institution to 79% in another

    -- there was no comment on what premedication was given in 3 of the 50 patients

    -- was there a selection bias in who got premedication?

    -- was there a difference in outcome based on the premedication?

    -- was there variability in second dose reactions in the 20% to had reactions based on what their initial symptoms were after the first dose?

    -- was there any difference between the Moderna and Pfizer vaccines, as suggested in http://gmodestmedblogs.blogspot.com/2021/02/covid-mrna-vaccine-anaphylaxis-overblown.html

    -- where there comorbidities or age groups that had different reactions between the first and second doses?

-- there also was no information on IgE-specific antibodies after the first dose, or if these mattered in terms of the type of reaction after the second dose; there was also no information on the antibody response to the first and second doses

-- this was a small study with relatively few people, including only 32 who had anaphylaxis, limiting generalizability to the larger population

    --30 of the 189 patients did not get a second dose. were they different in terms of their reactions? again, this could decrease generalizability

 

so, this study does provide some reassurance that the second dose of an mRNA vaccine can be given.

-- perhaps it does make sense to give a nonsedating antihistamine prior to the first second dose, since, as per the authors, those with a non-IgE mediated reaction may benefit

-- and, given the larger study on anaphylaxis (http://gmodestmedblogs.blogspot.com/2021/02/covid-mrna-vaccine-anaphylaxis-overblown.html ), it might make sense for people to be observed a full 45 minutes after the second injection

-- hopefully this paper and others will help clinicians/patients who had immediate reactions to the first shot get their second vaccine dose, which seems to be particularly important in our current scourge of delta variant:    see http://gmodestmedblogs.blogspot.com/2021/06/covid-vaccine-effectiveness-for-b16172.html  finding much less evident neutralizing antibody after only one dose

--http://gmodestmedblogs.blogspot.com/2021/07/covid-moderna-j-work-ag-delta-virus-and.html  for more recent info on delta variant

 

geoff

 

If you would like to be on the regular email list for upcoming blogs, please contact me at gmodest@uphams.org

 

to get access to all of the blogs (2 options):

1. go to http://gmodestmedblogs.blogspot.com/ to see them in reverse chronological order

2. click on 3 parallel lines top left, if you want to see blogs by category, then click on "labels" and choose a category​

3. or you can just click on the magnifying glass on top right, then  type in a name in the search box and get all the blogs with that name in them

 

or: go to https://www.bucommunitymedicine.org/ , a website from the Community Medicine section at Boston Medical Center.  This site does have a very searchable and accessible list of my blogs (though there have been a few that did not upload over the last year or two). but overall it is much easier to view blogs and displays more at a time.

 

 

please feel free to circulate this to others. also, if you send me their emails, i can add them to the list