Global Health Asia-Pacific July 2020 July 2020 | Page 66

Vaccine
Despite the
caution, a
reliable test
that can show
if a patient
has the virus
at the time of
screening is
already in use
and is being
constantly
improved
upon in terms
of the time
it takes to
produce a
result
Continued from page 62
bullet in the fight against coronavirus many believe it
to be.
Officials at the �.�. Centres for Disease Control
and �revention (CDC) noted in late May that there
was still far too much unknown about the coronavirus’
spread. They also raised questions about the accuracy
of various antibody tests in use, which are known to
provide incorrect results up to half the time.
The tests will eventually prove key in providing
a scientific basis for determining how and when to
reopen businesses and allow mass gatherings, but
we’re still far from that point, the CDC said in an
updated guidance about coronavirus antibody testing.
Even as scientists work to improve the reliability
of these tests, there’s still the issue of how immunity
works against the virus. The body typically produces
antibodies as a defense against viral invaders,
meaning that a patient who has recovered from a
disease like COVID-19 will have some level of immunity
to its pathogen.
�ut scientists still lack sufficient data about
immunity to COVID-19 because the virus is so
new. Even if the antibodies bring some immunity,
researchers don’t yet know how strong that immunity
is, how long it lasts, and whether recovered patients
are still at risk of reinfection.
This is why the CDC cautioned that blood tests
that detect antibodies �should not be used to make
decisions about grouping persons residing in or being
admitted to congregate settings, such as schools,
dormitories, or correctional facilities� and �should not
be used to make decisions about returning persons to
the workplace.�
Despite the caution, a reliable test that can show
if a patient has the virus at the time of screening
is already in use and is being constantly improved
upon in terms of the time it takes to produce a result.
Countries around the world have been using variations
of this test on their populations.
In May, the �.�. �ood and Drug Administration
(�DA) authorised a new category of tests that can
quickly detect fragments of proteins found on or within
the virus through samples collected from the nasal
cavity using swabs.
These so-called antigen tests are an improvement
over the previous polymerase chain reaction
(�CR) tests that had been used widely in countries
successfully controlling the novel coronavirus,
including �ermany and �outh �orea.
Though �CR tests are extremely accurate, running
them and analysing the results can take time. �y
contrast, the new antigen tests can provide results in
minutes. One drawback is that they might not detect
all active infections, as they don’t work the same way
as �CR tests.
Antigen tests are very specific to the virus but
are not as sensitive as molecular �CR tests. This
means that, while positive results from antigen tests
are highly accurate, negative results cannot rule
out infection because of the higher chance of false
negatives.
�Antigen tests will play a critical role in the fight
against COVID-19 and we will continue to offer
support and expertise to help with the development
of accurate tests, and to review and monitor marketed
tests to ensure accuracy, while balancing the urgent
need for these critical diagnostics,� the �DA said in a
statement.
Another ma�or challenge the pandemic has
posed for science is how to increase capacity for
diagnostic testing, said Dr Hadley �ikes, an MIT
associate professor of biomolecular engineering and
researcher at �MART, the university’s research centre
in �ingapore.
�It’s also given us a picture of what are our
capabilities, because I think all of the countries that
have been affected are as motivated as they can ever
be to deploy any of the technologies that they possibly
can to test as much of the population as they can,�
she told �lobal Health Asia-�acific.
Dr �ikes has spent much of this year flying
between �ingapore and her university in �oston as
part of the global research effort that’s hunting for a
reliable antigen test. The location of MIT’s outpost
in �ingapore has been critical in providing context
for a testing solution, having been at the centre of a
previous outbreak.
�After their experience in the early 2000s with
�AR�, �ingapore analysed the situation and put in
place public health measures to effectively manage
and contain an outbreak if it were to happen again.
�If you’re going to validate a new medical
diagnostic, �ingapore’s �ational Centre for Infectious
disease is the place to do it, with their organised
collection of samples and thoughtful study design,�
she said.
While scientists are making steady progress
on antibodies and testing, other researchers are
grappling with the much more elusive end goal of
developing a vaccine.
�ome experts predict a therapy will take a year
or more before it can go into widespread use. �et
scientists in China say their attempt at a vaccine has
already seen promising results after only a short trial.
The first coronavirus vaccine to make it to a phase
one clinical trial was found to safely generate an
immune response, according to research published
in The Lancet. Within a month of getting the Ad5
vectored COVID-19 �ab, most of the 108 participants
in the �ei�ing Institute of �iotechnology study saw a
four-fold increase in binding antibodies and a rapid
response from T cells which protect the body against
pathogens and cancer. Moreover, no severe negative
reactions were reported.
These results represent an �important milestone�,
according to �rofessor Wie Chen, who is responsible
for the research.
�The trial demonstrates that a single dose of the
new adenovirus type 5 vectored COVID-19 (Ad5-nCoV)
vaccine produces virus-specific antibodies and T cells
64 JULY 2020 GlobalHealthAndTravel.com