COVID-19 antibodies persist, reduce reinfection risk for up to six
months, study finds
The antibodies' ability to neutralize COVID-19 did not differ
significantly over the six-month period.

Date:
September 14, 2021
Source:
Michigan Medicine - University of Michigan
Summary:
Most patients with mild COVID-19 infections produce antibodies that
persist and protect them from reinfection for up to six months, a
new study found. The antibodies' ability to neutralize COVID-19 did
not differ significantly from the first visit, which occurred three
months after infection, to the second visit at the six-month mark.



FULL STORY ==========================================================================
A Michigan Medicine study found that most patients with mild COVID-19 infections produce antibodies that persist and protect them from
reinfection for up to six months.


========================================================================== Researchers analyzed nearly 130 subjects with PCR-confirmed COVID-19
illness between three and six months after initial infection. Three
patients were hospitalized while the rest were treated as outpatients
and experienced mild infection, with symptoms including headaches,
chills and loss of taste or smell.

The results, published in Microbiology Spectrum, reveal approximately
90% of participants produced spike and nucleocapsid antibody responses,
and all but one had persistent antibody levels at follow up.

"Previously, there was a lot of concern that only those with severe
COVID-19 produced strong antibody responses to infection," said Charles Schuler, M.D., lead author of the paper and clinical assistant professor
of allergy and immunology at Michigan Medicine. "We're showing that
people with mild bouts of COVID-19 did really well after their infection,
made antibodies, and kept them." The prospective study's participants
were either Michigan Medicine health care workers or patients with a
high risk of exposure to COVID-19. Most subjects took part in the same
research team's previous study, which found that COVID antibody tests
are effective at predicting prior infection.

During the observation period, none of the subjects who produced
antibodies were re-infected, compared to 15 antibody-negative
patients. Schuler's team also found that the antibodies' ability to
neutralize COVID-19 did not differ significantly from the first visit,
which occurred three months after infection, to the second visit at the six-month mark.



========================================================================== "While some studies have suggested antibodies against COVID-19 wane
over time, these findings provide strong prospective evidence for
longer-term immunity for those who produce an immune response to mild infection," said James Baker Jr., M.D., senior author of the paper and
founding director of the Mary H. Weiser Food Allergy Center at Michigan Medicine. "To our knowledge, this is the first prospective study that demonstrates such a risk reduction for clinical reinfection in this
specific type of population." Impact on COVID vaccination The team of researchers is now analyzing samples of this subject group taken up to a
year after infection to further evaluate antibody responses. Meanwhile,
they concluded that individuals with COVID-19 can delay vaccination
for 90 days after infection ends. The Centers for Disease Control
and Prevention recommends those treated with monoclonal antibodies
or convalescent plasma wait 90 days after receiving treatment before
getting vaccinated, and others should wait until they have recovered
from COVID-19 and "have met the criteria to discontinue isolation."
A study conducted in Kentucky that found that unvaccinated people who
already had COVID-19 were 2.34 times more likely than fully vaccinated
people to be infected again, suggesting "vaccination provides additional protection against reinfection." Additionally, the research was conducted between March 2020 and Feb. 2021, months before the highly transmissible
Delta variant became the dominant strain of COVID in the United States.

Amid rising cases and hospitalizations, Schuler said, remaining
unvaccinated comes with "a high price" for immunity.

"These results are encouraging for those who have already run
the gauntlet of COVID-19 infection," he said. "However, I do not
recommend citing this study as a reason not to be vaccinated
for those never previously infected. Vaccination decreases
infectiousness, the risk of hospitalization and deaths from
COVID-19, without having the actual infection. Achieving natural
immunity by deferring vaccination in favor of infection is not worth
going through the discomfort, risk to yourself and risk to others." ========================================================================== Story Source: Materials provided by
Michigan_Medicine_-_University_of_Michigan. Original written by Noah
Fromson. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Charles F. Schuler, Carmen Gherasim, Kelly O'Shea, David M. Manthei,
Jesse Chen, Cristyn Zettel, Jonathan P. Troost, Andrew A. Kennedy,
Andrew W. Tai, Donald A. Giacherio, Riccardo Valdez, James
L. Baldwin, James R.

Baker. Mild SARS-CoV-2 Illness Is Not Associated with
Reinfections and Provides Persistent Spike, Nucleocapsid, and
Virus-Neutralizing Antibodies. Microbiology Spectrum, 2021; DOI:
10.1128/spectrum.00087-21 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/09/210914184809.htm

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