There is now mounting studies that show that the antibody response from a single dose of either an mRNA or adenovirus-vectored vaccine in a person with prior COVID-19 disease is as good if not better than a naïve person with 2 shots of the mRNA vaccine.
I first alluded to this in a twitter message on 26 May 2021 with reference to my 92 year old uncle who had suffered from COVID-19 and had taken his first dose of the Pfizer mRNA vaccine. I attached with the tweet one of many studies which rationalized this approach with good scientific evidence. [1]
The restricted vaccine supply chain has led to various efforts to consider variable dosing strategies in an effort to budget vaccine doses and administer them to a wider coverage of the population. The delayed second dose regime practiced firstly and widely in the UK was discussed in an earlier article. [2]
This call for a dose sparing strategy, administering a single mRNA vaccine to persons with prior SARS-CoV-2 infection, has now been advocated by many scientists. [3,4,5]
Eric Topol, editor in chief of Medscape, on 10 Feb 2021 asked:
“How many studies are needed before we accept that people with prior covid-19 have a robust immune Ab response to a single dose of mRNA vaccines, like the 2nd dose for those with no prior covid?”
More recently, Michael Mina, Harvard Medical School, tweeted:
“To maximize vaccines to halt COVID-19, look to immunity When someone gets their first dose – they should be offered to take a finger prick blood sample at same time That should be tested for SARS-CoV-2 antibodies If positive, then don’t come back for a second dose.”
The RECoVERED Study Group concluded that:
“A single dose of BNT162b2 mRNA vaccine up to 15 months after SARS-CoV-2 infection provides neutralizing titers exceeding two vaccine doses in previously uninfected individuals. These findings support wide implementation of a single-dose mRNA vaccine strategy after prior SARS-CoV-2 infection.” [1]
Similar immune responses have been illustrated following a single-dose of an adenovirus-vectored vaccine. The authors of the study concluded: [3]
“Our data support that a single dose ChAdOx1 nCoV-19 vaccine serves as an effective immune booster after priming with natural SARS-CoV-2 infection up to at least 11 months post infection.”
The Health Care workers (HCW) in the study who had recovered from COVID-19 and had a single dose of the AstraZeneca vaccine (Covishield in India), not only produced more antibodies, but also made neutralizing antibodies which were active not only against the wild type virus but also against the P1 (Brazil) and B1351 (South Africa) variants of concern (VOC).
Malaysia now has clocked 526,000 cases of COVID-19 with 460,000 recovered cases (26 May 2021). There is an opportunity here to save about half a million doses of vaccine which can be offered to other COVID-19 naïve individuals.
These persons would also be saved from the potential experience of Adverse Effects Following Immunization (AEFI) which is more pronounced with the second dose of the vaccines.
I am keeping my fingers crossed and hoping that the MOH and the JKJAV is up to date with the latest dosing strategies and would not deny my 92 year old uncle his “vaccine passport” when he turns up at the vaccination center, not wanting the second dose based on scientific studies. [6,7,8,9,10,11)
References:
- https://www.medrxiv.org/content/10.1101/2021.05.25.21257797v1
- https://codeblue.galencentre.org/2021/05/19/delay-second-dose-of-covid-19-vaccines-to-protect-more-people-dr-musa-mohd-nordin/
- https://science.sciencemag.org/content/early/2021/04/29/science.abh1282
- https://www.nytimes.com/2021/02/19/health/covid-vaccine-single-dose.html
- https://www.wsj.com/articles/for-covid-19-survivors-one-shot-may-be-enough-preliminary-studies-show-11613903400?mod=searchresults_pos1&page=1
- https://www.medrxiv.org/content/10.1101/2021.05.08.21256866v1
- https://www.medrxiv.org/content/10.1101/2021.01.30.21250843v2.full.pdf
- https://www.medrxiv.org/content/10.1101/2021.01.29.21250653v1
- https://www.medrxiv.org/content/10.1101/2021.02.05.21251182v1.full.pdf
- https://www.nejm.org/doi/full/10.1056/NEJMc2103825
- https://www.medrxiv.org/content/10.1101/2021.02.07.21251311v1
Dr Musa Mohd Nordin
27 May 2021
