LONDON (Reuters) – A test in pigs of AstraZeneca (AZN.L) The experimental vaccine COVID-19 has found that two doses of the injection produce a greater antibody response than a single dose.
Research published Tuesday by Britain’s Pirbright Institute found that administering an initial main dose followed by a booster dose of the vaccine elicited a stronger immune response than a single dose. This suggests that a two-dose approach may be more effective in obtaining protection against COVID-19, the disease caused by the new coronavirus.
“The researchers saw a marked increase in neutralizing antibodies, which bind to the virus in a way that blocks infection,” the Pirbright team said in a statement. However, they added that it is not yet known what level of immune response will be required to protect humans.
The ChAdOx1 nCoV-19 vaccine, also known as AZD1222, was originally developed by scientists at the University of Oxford, who are now working with AstraZeneca in development and production.
“These results seem encouraging because the administration of two injections … increases the responses of antibodies that can neutralize the virus, but what is important is the response in humans,” said Bryan Charleston, Pirbright director.
AZD1222 is already in human trials, and AstraZeneca says it expects to have data on efficacy later this year.
Preliminary data from a trial in six monkeys found that some of the monkeys that received a single injection developed antibodies to the virus within 14 days, and all developed protective antibodies within 28 days.
More than 100 potential vaccines are being developed worldwide to try to control the pandemic, which has already killed hundreds of thousands of people.
Stephen Griffin, an associate professor at the University of Leeds who was not directly involved in this work, said it was “an encouraging development” and showed that “a strategy called” main thrust “leads to much better responses” than a single dose.
“While these studies will need to be repeated in human subjects … this is an encouraging study,” he said.
Reports from Kate Kelland, edition of Jason Neely and Jane Merriman