LONDON (Reuters) – Emerging evidence that the body’s immune defense against COVID-19 may be short-lived makes it even more difficult for vaccine developers to find vaccines fully capable of protecting people in future waves of infection, Scientists said Tuesday.
FILE PHOTO: Professor Gottfried Kremsner injects a coronavirus disease vaccine (COVID-19) from the German biotech company CureVac into a volunteer at the start of a series of clinical trials at his tropical institute at the university clinic in Tuebingen, Germany, June 22. 2020. REUTERS / Kai Pfaffenbach / File Photo
Preliminary studies in China, Germany, Britain, and elsewhere have found that patients infected with the new coronavirus produce protective antibodies as part of their immune system’s defenses, but these appear to last only a few months.
“Most people make them (antibodies), but they can often drop rapidly, suggesting there may be little immunity,” said Daniel Altmann, professor of immunology at Imperial College London.
According to experts, that poses major problems for developers of possible COVID-19 vaccines, and for public health authorities seeking to deploy them to protect populations from future waves of the pandemic.
“It means that over-reliance on a vaccine (to control the pandemic) is not wise,” said Stephen Griffin, associate professor of medicine at the University of Leeds.
To be truly effective, COVID-19 vaccines “will need to generate stronger and more durable protection … or they may need to be administered regularly,” he said.
“And those things are not trivial.”
More than 100 research teams and companies around the world are seeking to develop COVID-19 vaccines, and at least 17 are already in human trials to assess efficacy.
A preclinical trial in pigs with the AstraZeneca COVID-19 vaccine, known as AZD1222, showed that two doses produced a greater antibody response than a single dose.
So far, however, there is no human trial data showing whether any protective antibody immune response would be strong and long-lasting enough.
Booster shots
Jeffrey Arnold, visiting professor of microbiology at Oxford University in Britain and a former expert on Sanofi Pasteur, said one reason for the lack of data is simply time: high-speed development and testing of possible coronavirus vaccines They have been running for just six months. – Not enough to show the longevity of any protection they offer.
He and other vaccine and immunology experts also said it doesn’t necessarily follow that waning immunity in natural cases of COVID-19 infection would be the same with the vaccine-induced immune response:
“If we can, we would like to improve nature,” he said in a telephone interview. “With vaccines, of course, we are not directly infecting the virus, but we present the surface protein administered by a different vector, or made in the laboratory and injected into the arm … so the ideal goal is to do it better than the infection itself by making the immunity of the vaccine even stronger than the natural one. ”
Griffin said one approach could be that when developing viable vaccines, authorities should consider giving booster vaccines to millions of people at regular intervals, or even combining two or more types of vaccines in each person to get the best possible protection.
Practically, however, that presents a great challenge. “Giving the whole world even a dose of a vaccine is one thing,” he said. “Giving them multiple doses is a very different one.”
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