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Two teams tested two of the new variants against blood drawn from people who had received the full dose of two courses of Moderna or Pfizer vaccine.
While mutations in the new virus variants – one first seen in Britain and the other first identified in South Africa – allowed them to evade some of the induced immunity by vaccination, it was far from a complete escape, the two teams reported separately.
A team led by Dr Michel Nussenzweig of Rockefeller University tested plasma collected from 20 people who received two doses of Pfizer / BioNTech or Moderna vaccine in clinical trials.
They found that vaccines produced strong antibody responses, as well as cells that kept making new antibodies for months or years. “We measured their antibody responses to the wild type virus. Then we took their plasmas and measured them against the variants,” Nussenzweig told CNN.
Wild-type virus is the catch-all name for the virus that is generally circulating and is not sufficiently modified to be referred to as a variant.
“When you start to put all of these antibody mixes together, it means that together they can take care of the variants,” Nussenzweig said. Even though they had a reduced effect, overall the response was so overwhelming that it shouldn’t matter, he said.
“What we really want to do with these vaccines is prevent people from entering the hospital. They are extremely likely to do so, regardless,” added Nussenzweig.
Eventually, the vaccines should be updated – but the new mRNA vaccines made by Pfizer and Moderna can be changed very quickly. “Should vaccines be changed?” He asked. “Probably – but that doesn’t mean they won’t be effective.”
“More data is needed to monitor the effectiveness of the Pfizer-BioNTech COVID-19 vaccine in preventing COVID-19 caused by new virus variants,” the companies said in a joint statement.
“So far, for COVID-19 vaccines, it has not been established what reduction in neutralization could indicate the need for a vaccine strain change. If a vaccine strain change was required to handle virus variants in the future, the companies believe that the flexibility of BioNTech’s proprietary mRNA vaccine platform is well suited to allow such an adjustment. ”
Moderna and Pfizer vaccines are designed to be quick and easy to adjust.
The coronavirus is constantly mutating, like many other viruses. Compared to the flu, the changes were slow and did not seem to affect the severity of illness caused by the infection.
But at least two of the variants – one first seen in Britain and known as B.1.1.7 and another first noticed in South Africa and known as B. 1,351 – seem to make the virus more contagious.
Scientists rushed to see if the changes in the virus would also make it vulnerable to available treatments and vaccines.
Earlier this week, Penny Moore, associate professor at the National Institute of Communicable Diseases in South Africa, released another preprinted study showing that people who have recovered from wild-type coronavirus infection could be slightly more sensitive to B.1.135.
They tested the antibody-rich blood serum of 44 people who had survived coronavirus infections before September. Half of the people showed an antibody response that should not fight the variant.
Nussenzweig said it was not surprising.
“A little difference in the plasma neutralization activity is something we need to pay attention to, but it is not a cause for alarm,” he said.
“There is a huge diversity in the breadth of responses people receive,” he added. “You don’t need to be immunocompromised and you may still not be creating a good response to this virus. People’s immune systems are as diverse as any human characteristic – for example, beauty, intelligence, hair color, your height. the immune system is no different. ”
Nussenzweig said his team’s experiences indicate that it may be weaker immune responses that help give rise to the coronavirus variants. The longer a person is infected, the more likely it is that the virus that infects them will mutate.
“Antibodies can select for these variants,” he said.
If a microbe is not completely stopped by the immune response, the variations that are most resistant to the immune response will be those that survive.
“If people do a suboptimal response, they might start to select these variants,” Nussenzweig said.
This is why scientists say it’s important to get as many people vaccinated as possible as quickly as possible, so that the virus stops circulating and therefore mutates.
Nussenzweig said his experiments so far indicate that the immune response elicited by the vaccination is several times larger and stronger than what would be needed to control the virus.
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