While there is no evidence that people vaccinated with either vaccine have less protection against variants, both companies said they have begun looking for ways to account for evolving mutations.
Of particular concern is variant B.1.351 seen for the first time in South Africa. He carries a mutation that helps him evade the body’s immune response to infection. The B.1.1.7 variant first seen in the UK is also of concern, as its mutations appear to make it more transmissible, so it spreads better and can also cause more serious illnesses.
Researchers are also finding variants in the United States that have developed mutations that help them bypass the immune system.
Pfizer and its partner BioNTech said Thursday that they have begun testing the extent to which protection against new variants is to add a third dose of the authorized vaccine.
The study will examine the safety and immune response of a booster dose in up to 144 participants from the previous phase 1 trial in the United States, including a subset of adults older than 85 years. It will also involve testing the extent to which their antibodies are able to neutralize “varieties of interest” in the lab, the companies said.
Volunteers would receive a third dose between 6 and 12 months after the previous two doses. The dose would be identical to the one currently authorized: 30 micrograms.
“This booster study is critical to understanding the safety of a third dose and the effectiveness against circulating strains,” Dr. Albert Bourla, CEO of Pfizer, in a statement.
Separately, Pfizer and BioNTech are also “in ongoing talks with regulatory authorities” about the possibility of testing a modified vaccine to protect it against variants in a 1/2 phase study.
However, Bourla noted that companies have not yet seen convincing evidence that the variants are resistant to the vaccine, although they are taking steps to prepare them.
Moderna said Wednesday afternoon that it has produced an updated version of its Covid-19 vaccine to help it combat the B.1.351 variant first seen in South Africa. Initial doses have been sent to the National Institutes of Health for a clinical study.
The new vaccine, called mRNA-1273351, will be evaluated as a booster for people who have already been vaccinated against coronavirus and as a primary vaccine for people who have not had coronavirus and have not yet been vaccinated. .
Modern said it will also evaluate a “multivalent” booster shot that combines the new vaccine formulation with the current vaccine.
In addition, the company said it has begun testing whether a lower third dose of the current Covid-19 vaccine can boost immunity to the coronavirus variants of concern, as some study participants are already receiving third doses.
“We are making rapid progress in testing vaccine updates that address emerging variants of the virus in the clinic. Modern is committed to making as many updates to our vaccine as necessary until the pandemic is under control. We hope to show that doses of reinforcement, if necessary, can be done at lower dose levels, which will allow us to provide many more doses to the global community by the end of 2021 and 2022 if needed, “said Stephane Bancel, CEO of Moderna in a statement.
Moderna did not say how long it would take for the studies to take or when the new vaccine would be available, if authorized. The current vaccine makes two doses of 100 micrograms spaced approximately a month apart. New booster doses are being evaluated at half of this level and below.
On Monday, the U.S. Food and Drug Administration announced new guidelines that would streamline and speed up the process of upgrading vaccines to target variants. An agency official estimated that this could involve several hundred individuals and take a few months.
“It will be on the order of a few hundred individuals in terms of size and we would expect this to take a few months,” Drs. Peter Marks, director of the FDA’s Center for Biological Assessment and Research, during a call with reporters Monday.
Both the Moderna and Pfizer vaccines use a new technology that uses messenger RNA or mRNA that simply requires a genetic code. The design aims to make vaccines easy to upgrade quickly, without the months of preparation needed to change an flu vaccine, for example.