* Russia has licensed potential coronavirus vaccine
* The Lancet has published results of early-stage trials
* Russian wealth fund chief says results answer critics
By Polina Ivanova and Andrew Osborn
MOSCOW, Sept 4 (Reuters) - Russia's "Sputnik-V" COVID-19
vaccine produced an antibody response in all participants in
early-stage trials, according to results published on Friday by
The Lancet medical journal that were hailed by Moscow as an
answer to its critics.
The results of the two trials, conducted in June-July this
year and involving 76 participants, showed 100% of participants
developing antibodies to the new coronavirus and no serious side
effects, The Lancet said.
Russia licensed the two-shot jab for domestic use in August,
the first country to do so and before any data had been
published or a large-scale trial begun. "The two 42-day trials – including 38 healthy adults each –
did not find any serious adverse effects among participants, and
confirmed that the vaccine candidates elicit an antibody
response," The Lancet said.
"Large, long-term trials including a placebo comparison, and
further monitoring are needed to establish the long-term safety
and effectiveness of the vaccine for preventing COVID-19
infection," it said.
The vaccine is named Sputnik-V in homage to the world's
first satellite, launched by the Soviet Union. Some Western
experts have warned against its use until all internationally
approved testing and regulatory steps have been taken.
But with the results now published for the first time in an
international peer-reviewed journal, and with a 40,000-strong
later-stage trial launched last week, a senior Russian official
said Moscow had faced down its critics abroad.
"With this (publication) we answer all of the questions of
the West that were diligently asked over the past three weeks,
frankly with the clear goal of tarnishing the Russian vaccine,"
said Kirill Dmitriev, the head of the Russian Direct Investment
Fund (RDIF), Russia's sovereign wealth fund, which has backed
the vaccine.
"All of the boxes are checked," he told Reuters. "Now... we
will start asking questions of some of the Western vaccines."
Dmitriev said at least 3,000 people had already been
recruited for the large-scale trial of the Sputnik-V vaccine
launched last week, and initial results were expected in October
or November this year. Commenting on the results of the early-stage trials, lead
author Dr Naor Bar-Zeev of the International Vaccine Access
Center, Johns Hopkins Bloomberg School of Public Health, USA
said the studies were "encouraging but small".
Bar-Zeev, who was not involved in the study, said "clinical
efficacy for any COVID-19 vaccine has not yet been shown."
RACE TO DEVELOP VACCINE
Governments and big pharmaceutical firms are racing to
develop a vaccine to end the COVID-19 pandemic, which has killed
more than 850,000 people globally and infected around 26
million.
More than half a dozen drugmakers are already conducting
advanced clinical trials, each with tens of thousands of
participants and several, including Britain's AstraZeneca
AZN.L and U.S. drugmakers Moderna MRNA.O and Pfizer PFE.N
expect to know if their COVID-19 vaccines work and are safe by
the end of this year.
The Lancet said the early-stage trials suggested the
Sputnik-V vaccine produced a response in a component of the
immune system known as T cells.
Scientists have been scrutinising the role played by T cells
in battling coronavirus infection, with recent findings showing
these cells may provide longer-term protection than antibodies.
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The vaccine, developed by Moscow's Gamaleya Institute, is
administered in two doses, with each based on a different vector
that normally causes the common cold: human adenoviruses Ad5 and
Ad26.
Some experts have said that using this delivery mechanism
could make a COVID-19 vaccine less effective, since many people
have already been exposed to the Ad5 adenovirus and developed
immunity to it. In China and the United States, about 40% of people have
high levels of antibodies from prior Ad5 exposure. In Africa, it
could be has high as 80%, experts have said.
Denis Logunov, one of the vaccine's developers at the
Gamaleya Institute, told Reuters the vaccine uses a strong
enough dose of Ad5 to overcome any earlier immunity, without
compromising safety.
The booster dose, based on the rarer Ad26 adenovirus,
provides further support because the likelihood of widespread
immunity to both types in the population is minimal, he said.
Russia has said it expects to produce between 1.5 million
and 2 million doses per month of its potential COVID-19 vaccine
by the end of the year, gradually increasing production to 6
million doses a month.