Infectious Disease

One dose of mRNA vaccine could also be sufficient for a beforehand contaminated particular person

March 10, 2021

2 min read

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Samanovic-Golden MI et al. Abstract 119LB. Presented at: Conference on Retroviruses and Opportunistic Infections; 6-10 March 2021 (virtual meeting).

Disclosure:
Krammer reports that he received grants from the JPB Foundation, the National Institute for Allergies and Infectious Diseases, and the Open Philanthropy Project during the study. Pfizer grants and personal fees; Avimex and Seqirus personal fees outside of this study; and have a patent for a serological assay to detect upcoming SARS-CoV-2 seroconversion. Mulligan reports that he has received consulting or consulting fees from Meissa Vaccines and outstanding research grants / grants from Eli Lilly and Company and Pfizer. Saadat does not report any relevant financial information. In the study you will find all relevant financial information from all other authors.

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Findings from several studies suggest that halving the two-dose series of COVID-19 messenger RNA vaccines may be enough to protect people who have recovered from COVID-19.

The first study presented at the virtual conference on retroviruses and opportunistic infections evaluated samples taken from study participants before and 6-14 days after dosing one and two of the messenger RNA (mRNA) vaccines.

Mark Mulligan quote

“People with known past COVID-19 were excluded from Phase 3 efficacy studies with COVID-19 vaccines.” Mark J. Mulligan, MD, F.IDSA, said Healio, director of the Langone Health Vaccine Center at New York University. “With the introduction of the EUA vaccines (Emergency Use Authorization) we had the opportunity to compare the vaccination reactions in SARS-CoV-2-experienced people with those in naive people.”

The study included 21 adults who received the Pfizer BioNTech vaccine and one who received the Moderna vaccine. According to Mulligan and colleagues, the 14 people enrolled in the study “produced binding and neutralizing antibody titers similar to or higher than those of SARS-CoV-2 naïve people who received 2 doses after 6 to 14 days. “In addition, the researchers found that a second dose of vaccine did not increase titers.

Florian Krammer

“With no prior infection, the first dose is important to build memory and the second dose is really important to increase avidity and increase antibody-secreting cells,” said Mulligan.

Mulligan said it would be beneficial to compare one dose to two doses of the mRNA vaccines in people who have recovered from COVID-19 and assess their immune responses over time.

“I am currently not in favor of any changes to the vaccination recommendation. We don’t know enough yet, ”he said. “Two doses of mRNA vaccines are the standard for public health according to the EEA.”

“Requires investigation”

Florian Krammer, PhD, A professor of vaccination science at the Icahn School of Medicine at Mount Sinai in New York and colleagues also studied the antibody responses in seropositive individuals after a single dose of mRNA vaccine.

They used the ongoing PARIS study to examine antibody responses in 110 people ⎼⎼ 67 seronegative and 43 seropositive ⎼⎼ who have received a first dose of any of the vaccines.

According to the study, which was published in a letter in the New England Journal of Medicine on Wednesday, “repeated sampling after the first dose shows that the majority of seronegative participants have variable and relatively low levels of SARS-CoV-2 within 9 to 12 IgG reactions had days after vaccination ”, while participants who already had SARS-CoV-2 antibodies“ quickly developed uniform, high antibody titers within days of vaccination ”.

Krammer and colleagues reported that the antibody titers of the participants in the latter group “at the same point in time after the first vaccine dose were 10 to 45 times higher than those of vaccines without pre-existing immunity … and also exceeded the mean antibody titers measured in the participants without beforehand existing immunity.

They said that the antibody titers of the vaccines without pre-existing immunity increased by a factor of 3 after the second vaccine dose, but no increase was seen in COVID-19 survivors after their second dose.

“We found that a single dose of an mRNA vaccine elicited rapid immune responses in seropositive participants, with post-vaccination antibody titers similar to or greater than the titers of seronegative participants who received two vaccinations,” they wrote. “It remains to be investigated whether a single dose of an mRNA vaccine provides effective protection in seropositive individuals.”

Degree in health care

A recent paper published in JAMA reported similar results in healthcare workers who were previously infected and subsequently vaccinated.

Saman Saadat, PhD, A postdoctoral fellow at the University of Maryland School of Medicine Department of Human Virology and colleagues are evaluating the results of a hospital-wide Serosurvey study conducted July through August 2020 at the University of Maryland Medical Center.

According to the study, participants were contacted at random based on stratification into three groups SARS-CoV-2 IgG antibody negative (Ab negative), IgG positive positive asymptomatic COVID-19 (asymptomatic) and IgG positive with a history of symptomatic COVID- 19 (symptomatic)) and were vaccinated with one of the two mRNA vaccines.

Of the 3,816 health care workers enrolled in the study, 151 were contacted at random and 59 volunteers enrolled 17 in the ab-negative group, 16 in the asymptomatic group, and 26 in the symptomatic group. According to the study, on days 0, 7 and 14 the mean reciprocal half-maximal binding titers in each of the asymptomatic (208, 29,364 and 34,033) and symptomatic (302, 32,301 and 35,460) groups were higher than in the ab-negative group (<50, <50 and 924) (P <0.001).

Additionally, the researchers found that on days 0 and 14, the mean reciprocal ID99 virus neutralization titers – “the 99% inhibitory dose, the highest dilution at which 99% of the cells were protected” – of each of the asymptomatic (80 and 40,960) and The symptomatic (320 and 40,960) groups were higher than the ab-negative group (<20 and 80) (P <0.001).

“Health care workers with previous COVID-19 infection, based on laboratory-confirmed serological tests, responded to a single dose of mRNA vaccine with a higher antibody titre than those who were not previously infected,” Saadat and colleagues wrote. “Given the ongoing global vaccine shortage, the results suggest a single-dose vaccination strategy for those with previous COVID-19 or a lower vaccination priority list.”

References:

Krammer F et al. New Engl J Med. 2021; doi: 10.1056 / NEJMc21.1667.

Samanovic-Golden MI et al. Abstract 119LB. Presented at: Conference on Retroviruses and Opportunistic Infections; 6-10 March 2021 (virtual meeting).

Saadat S. et al. JAMA. 2021; doi: 10.1001 / jama.2021.3341.

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Gitanjali Pai, MD, AAHIVS, FIDSA)

Gitanjali Pai, MD

At a crucial time in this pandemic, when vaccines are now available, if only to a limited extent, careful use of resources must be a priority, at least initially. This adds to new evidence suggesting that only a single dose of mRNA vaccine is required for those previously infected with SARS-CoV-2. Administering vaccines once to previously infected patients is not only an attractive consideration from an individual perspective; The logistics of two doses, side effects, etc., but also allows for a higher level of immunity to be accelerated in the population. We’ll climb out of this pandemic sooner if this approach has been shown to give adequate levels of immunity. Of course, more data and larger studies will be critical in making changes to the recommendations to the current two-dose regimens as investigated in their respective large-scale clinical studies.

Gitanjali Pai, MD

Member of the editorial team for infectious diseases

Adjunct Clinical Assistant Professor of Rural Health – Internal Medicine / Infectious Diseases

Oklahoma State University

Infectious Disease Doctor

Memorial hospital and medical clinic

Stilwell, Oklahoma

Disclosure: Pai does not report any relevant financial information.

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Conference on Retroviruses and Opportunistic Infections (CROI)

Conference on Retroviruses and Opportunistic Infections (CROI)

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