New study boosts hopes for a broad vaccine to combat COVID-19 variants
and future coronavirus outbreaks
Study fuels hopes for a 'dream vaccine' that can protect against current
and future coronavirus threats

Date:
August 19, 2021
Source:
Duke-NUS Medical School
Summary:
New research suggests the feasibility of a 'dream' vaccine that
not only protects against SARS-CoV-2 and its known variants of
concern, but also future VOCs and other animal coronaviruses with
known potential to cause severe disease in humans.



FULL STORY ========================================================================== Scientists from Duke-NUS Medical School and the National Centre for
Infectious Diseases (NCID) found that 2003 SARS survivors who have
been vaccinated with the Pfizer-BioNTech mRNA vaccine produced highly
potent functional antibodies that are capable of neutralising not only
all known SARS-CoV-2 variants of concerns (VOCs) but also other animal coronaviruses that have the potential to cause human infection. This
finding, published in the New England Journal of Medicine, is the first
time that such cross-neutralising reactivity has been demonstrated
in humans, and further boosts hopes of developing an effective and broad-spectrum next-generation vaccine against different coronaviruses.


========================================================================== Among the coronavirus family, one sub-group relies on the ACE2 molecule
to enter human cells. Both SARS-CoV-1 and SARS-CoV-2 belong to this
group as well as a number of coronaviruses circulating in animals such
as bats, pangolins and civets. While the exact route of transmission
remains unknown, these viruses have the potential to jump from animals
to humans and could start the next pandemic. Collectively, this group
of viruses is called sarbecovirus.

"We explored the possibility of inducing pan-sarbecovirus neutralising antibodies that can block the common human ACE2-virus interaction, which
will be protective not only against all known and unknown SARS-CoV-2 VOCs,
but also future sarbecoviruses," said Dr Chee Wah Tan, Senior Research
Fellow with Duke- NUS' Emerging Infectious Diseases (EID) Programme and co-first author of this study.

To test their hypothesis, researchers recruited eight people who recovered
from SARS-CoV-1, which was responsible for the 2003 SARS epidemic, as well
as ten healthy people and ten COVID-19 survivors. They then compared the
immune response of the three groups before and after they were vaccinated
with the SARS-CoV-2 vaccine. In particular, they wanted to understand
whether the neutralising antibodies developed in SARS-Vaccinated group
could wipe out both SARS-CoV-1 and SARS-CoV-2 viruses as well as other sarbecoviruses, including potentially zoonotic sarbecoviruses that have
been identified in bats and pangolins.

"Prior to vaccination, SARS-CoV-1 survivors had detectable neutralising antibodies against SARS-CoV-1 but no or low-level anti-SARS-CoV-2
neutralising antibodies. After receiving two doses of the mRNA vaccine,
all displayed high levels of neutralising antibodies against both
SARS-CoV-1 and SARS-CoV-2," said Dr Wanni Chia, Research Fellow at
the Duke-NUS EID' programme and co-first author of this study. "Most importantly, they are the only group with a broad spectrum of
neutralising antibodies against ten sarbecoviruses that were chosen to
be examined." "Our study points to a novel strategy for the development
of next-generation vaccines, which will not only help us control the
current COVID-19 pandemic, but may also prevent or reduce the risk of
future pandemics caused by related viruses," said Professor Wang Linfa
from Duke-NUS EID programme, who is the senior corresponding author of
this study.

"Professor Wang's team made an astute serendipitous observation in
an ongoing national multicentre immune monitoring study of COVID-19
vaccination called the Singapore COVID-19 Vaccine Immune Response and Protection Study (SCOPE), which is coordinated by NCID. As emerging
variants of concern have already demonstrated some degree of immune
evasion against the first-generation vaccines, this discovery has
the potential to address that problem as the world continues COVID-19 vaccination to exit the pandemic. In addition, this can potentially act
as a highly promising preventive vaccine against future coronavirus
pandemics," said Associate Professor David Lye, Director, Infectious
Disease Research and Training Office, NCID and joint corresponding author
of the study.

The team conducted their investigation using an improved version of
the surrogate virus neutralisation test (sVNT) developed by Duke-NUS in
early 2020.

Prof Wang and his team invented the sVNT assay, trade named cPassTM,
which has been granted Emergency Use Authorisation by the US FDA to
determine SARS-CoV-2- specific neutralising antibodies in human sera
following infection or vaccination. Dr Tan and Dr Chia are part of
Prof Wang's team and co-inventors of the sVNT. The improved multiplex
sVNT allows simultaneous detection of neutralising antibodies against
different sarbecoviruses in a single tube, thus playing a pivotal role
in studies like this that require accurate side-by-side comparison of neutralising antibody levels against different viruses.

The team is currently conducting a proof-of-concept study to develop
a third- generation vaccine against different coronaviruses (3GCoVax)
as well as broad neutralising antibodies for therapy and is looking to
recruit individuals who recovered from SARS infection in 2003.

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


========================================================================== Journal Reference:
1. Chee-Wah Tan, Wan-Ni Chia, Barnaby E. Young, Feng Zhu, Beng-Lee
Lim, Wan-
Rong Sia, Tun-Linn Thein, Mark I.-C. Chen, Yee-Sin Leo, David
C. Lye, Lin-Fa Wang. Pan-Sarbecovirus Neutralizing Antibodies in
BNT162b2- Immunized SARS-CoV-1 Survivors. New England Journal of
Medicine, 2021; DOI: 10.1056/NEJMoa2108453 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210819113028.htm

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