Antibodies to SARS-CoV-2 remain stable, or even increase, seven months
after infection
The SEROCOV study also provides evidence that pre-existing antibodies to common cold coronaviruses may be protective

Date:
August 6, 2021
Source:
Barcelona Institute for Global Health (ISGlobal)
Summary:
The levels of IgG antibodies against SARS-CoV-2 Spike protein remain
stable, or even increase, seven months after infection, according
to a follow-up study in a cohort of healthcare workers. The results
also support the idea that pre-existing antibodies against common
cold coronaviruses could protect against COVID-19.



FULL STORY ==========================================================================
The levels of IgG antibodies against SARS-CoV-2 Spike protein remain
stable, or even increase, seven months after infection, according to
a follow-up study in a cohort of healthcare workers coordinated by
the Barcelona Institute for Global Health (ISGlobal), an institution
supported by "la Caixa" Foundation, in collaboration with the Hospital
Clinic of Barcelona. The results, published in Nature Communications,
also support the idea that pre-existing antibodies against common cold coronaviruses could protect against COVID-19.


==========================================================================
In order to predict the pandemic's evolution and develop effective
strategies, it is critical to better understand the dynamics and duration
of immunity to SARS-CoV-2 as well as the possible role of pre-existing antibodies against the coronaviruses that cause common colds. With this
goal in mind, the team led by ISGlobal researcher Carlota Doban~o followed
a cohort of healthcare workers at the Hospital Clinic (SEROCOV study)
from the beginning of the pandemic, in order to evaluate the levels
of antibodies against different SARS-CoV- 2 antigens over time. "This
is the first study that evaluates antibodies to such a large panel of SARS-CoV-2 antibodies over 7 months," says Doban~o.

The research team analysed blood samples from 578 participants, taken
at four different timepoints between March and October 2020. They used
the Luminex technology to measure, in the same sample, the level and
type of IgA, IgM or IgG antibodies to 6 different SARS-CoV-2 antigens
as well as the presence of antibodies against the four coronaviruses
that cause common colds in humans.

They also analysed the neutralising activity of antibodies in
collaboration with researchers at the University of Barcelona. The study
had funding from the European innovation network EIT Health.

The results show that the majority of infections among healthcare workers occurred during the first pandemic wave (the percentage of participants
with SARS-CoV-2 antibodies increased only slightly between March and
October -- from 13.5% to 16.4%). With the exception of IgM and IgG
antibodies against the nucleocapsid (N), the rest of IgG antibodies
(including those with neutralising activity) remained stable over time, confirming results from other recent studies.

"Rather surprisingly, we even saw an increase of IgG anti-Spike antibodies
in 75% of the participants from month five onwards, without any evidence
of re- exposure to the virus," says Gemma Moncunill, senior co-author
of the study. No reinfections were observed in the cohort.

Regarding antibodies against human cold coronaviruses (HCoV), the results suggest that they could confer cross-protection against COVID-19 infection
or disease. People who were infected by SARS-CoV-2 had lower levels of
HCoV antibodies. Moreover, asymptomatic individuals had higher levels of anti-HCoV IgG and IgA than those with symptomatic infections. "Although cross-protection by pre-existing immunity to common cold coronaviruses
remains to be confirmed, this could help explain the big differences in susceptibility to the disease within the population," says Doban~o.

========================================================================== Story Source: Materials provided by Barcelona_Institute_for_Global_Health_(ISGlobal). Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. Natalia Ortega, Marta Ribes, Marta Vidal, Roci'o Rubio, Ruth
Aguilar,
Sarah Williams, Diana Barrios, Selena Alonso, Pablo Herna'ndez-Luis,
Robert A. Mitchell, Chenjerai Jairoce, Angeline Cruz, Alfons
Jimenez, Rebeca Santano, Susana Me'ndez, Montserrat Lamoglia,
Neus Rosell, Anna Llupia`, Laura Puyol, Jordi Chi, Natalia
Rodrigo Melero, Daniel Parras, Pau Serra, Edwards Pradenas,
Benjamin Trinite', Julia` Blanco, Alfredo Mayor, Sonia Barroso,
Pilar Varela, Anna Vilella, Antoni Trilla, Pere Santamaria,
Carlo Carolis, Marta Tortajada, Luis Izquierdo, Ana Angulo,
Pablo Engel, Alberto L. Garci'a-Basteiro, Gemma Moncunill,
Carlota Doban~o. Seven-month kinetics of SARS-CoV-2 antibodies and
role of pre- existing antibodies to human coronaviruses. Nature
Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-24979-9 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210806104337.htm

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