For unvaccinated, reinfection by SARS-CoV-2 is likely

Date:
October 4, 2021
Source:
University of North Carolina at Charlotte
Summary:
Throughout the COVID-19 pandemic, there has been much uncertainty
about how long immunity lasts after someone who is unvaccinated
is infected with SARS-CoV-2. Now scientists have an answer. Strong
protection following natural infection is short-lived.



FULL STORY ========================================================================== Throughout the COVID-19 pandemic, there has been much uncertainty about
how long immunity lasts after someone who is unvaccinated is infected
with SARS- CoV-2.


==========================================================================
Now a team of scientists led by faculty at Yale School of Public Health
and the University of North Carolina at Charlotte have an answer. Strong protection following natural infection is short-lived.

"Reinfection can reasonably happen in three months or less," said Jeffrey Townsend, the Elihu Professor of Biostatistics at the Yale School of
Public Health and a lead author of the study. "Therefore, those who have
been naturally infected should get vaccinated. Previous infection alone
can offer very little long-term protection against subsequent infections."
The study, published in the journal The Lancet Microbe, is the first to determine the likelihood of reinfection following natural infection and
without vaccination.

Townsend and his team analyzed known reinfection and immunological data
from the close viral relatives of SARS-CoV-2 that cause "common colds" --
along with immunological data from SARS-CoV-1 and Middle East Respiratory Syndrome.

Leveraging evolutionary principles, the team was able to model the risk
of COVID-19 reinfection over time.

Reinfections can and have happened, even shortly after recovery. And
they will become increasingly common as immunity wanes and new SARS-CoV-2 variants arise.

"We tend to think about immunity as being immune or not immune. Our
study cautions that we instead should be more focused on the risk of reinfection through time," said Alex Dornburg, assistant professor
of bioinformatics and genomics at the University of North Carolina
at Charlotte, who co-led the study with Townsend. "As new variants
arise, previous immune responses become less effective at combating
the virus. Those who were naturally infected early in the pandemic are increasingly likely to become reinfected in the near future." The team's data-driven model reveals striking similarities to the reinfection risks
over time between SARS-CoV-2 and endemic coronaviruses.

"Just like common colds, from one year to the next you may get reinfected
with the same virus. The difference is that, during its emergence in
this pandemic, COVID-19 has proven to be much more deadly." said Townsend.

"Due to the ability of SARS-CoV-2 to evolve and reinfect, it, too, is
likely to transition from pandemic to an endemic disease," added Dornburg.

"A hallmark of the modern world is going to be the evolution of new
threats to human health," said Townsend. "Evolutionary biology --
which provided the theoretical foundations for these analyses -- is traditionally considered a historical discipline. However, our findings underscore its important role in informing decision-making, and provide
a crucial stepping stone toward robust knowledge of our prospects of
resistance to SARS-CoV-2 reinfection." Co-authors include researchers
from Temple University. Funding for the research was provided by the
U.S. National Science Foundation.

========================================================================== Story Source: Materials provided by
University_of_North_Carolina_at_Charlotte. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Jeffrey P Townsend, Hayley B Hassler, Zheng Wang, Sayaka Miura,
Jaiveer
Singh, Sudhir Kumar, Nancy H Ruddle, Alison P Galvani, Alex
Dornburg. The durability of immunity against reinfection by
SARS-CoV-2: a comparative evolutionary study. The Lancet Microbe,
2021; DOI: 10.1016/S2666-5247 (21)00219-6 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/10/211004104303.htm

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