While there is no evidence that people immunized with either vaccine have less protection against the variants, both companies said they started looking for ways to account for evolving mutations.
Especially worrying is variant B.1.351 seen for the first time in South Africa. It carries a mutation that helps it prevent the body’s immune response to infection. Variant B.1.1.7 seen for the first time in the UK is also causing 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 escape the immune system.
Pfizer and its partner BioNTech said on Thursday that they have started testing how well adding a third dose of their authorized vaccine can protect against new variants.
The study will look at the safety and immune response of a booster dose in up to 144 participants in the previous Phase 1 study in the U.S., including a subset of older adults up to 85 years old. It will also involve testing how well your antibodies are able to neutralize “strains of interest” in the laboratory, the companies said.
The volunteers would receive a third dose between 6 and 12 months after the first two doses. The dosage would be identical to that currently authorized: 30 micrograms.
“This reinforcement study is critical to understanding the safety of a third dose and effectiveness against circulating strains,” said Pfizer CEO, Dr. Albert Bourla, in a statement.
Separately, Pfizer and BioNTech are also “in ongoing discussions with regulatory authorities” about the potential to test a modified vaccine to protect against variants in a Phase 1/2 study.
However, Bourla noted that the companies have yet to see convincing evidence that the variants are resistant to the vaccine, although they are taking steps to prepare.
Moderna said on Wednesday that it produced an updated version of its Covid-19 vaccine to help it fight variant B.1.351 seen for the first time in South Africa. Initial doses were sent to the National Institutes of Health to a clinical study.
The new vaccine, called mRNA-1273,351, will be evaluated as a booster injection 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.
Moderna said it will also evaluate a “multivalent” booster injection that combines the new vaccine formulation with the current vaccine.
In addition, the company said it has started testing whether a lower third dose of its current Covid-19 vaccine can boost immunity against coronavirus variants of concern, with some study participants already receiving the third dose.
“We are moving quickly to test updates to vaccines that address emerging variants of the virus in the clinic. Moderna is committed to making as many updates to our vaccine as necessary until the pandemic is under control. We hope to demonstrate that booster doses, if necessary , can be done with lower dose levels, which will allow us to deliver many more doses to the global community in late 2021 and 2022, if necessary, “said Stephane Bancel, CEO of Moderna, in a statement.
Moderna did not say how long the studies are waiting or when the new vaccine will be available, if authorized. The current vaccine requires two doses of 100 micrograms with an interval of about a month. The new booster doses are being evaluated at half that level or less.
On Monday, the U.S. Food and Drug Administration announced new guidelines that would streamline and accelerate the process of updating vaccines for specific variants. An agency official estimated that this could involve several hundred people and take a few months.
“It will be in the order of a few hundred individuals in terms of size and we hope it will take a few months,” said Dr. Peter Marks, director of the FDA’s Center for Biological Research and Evaluation, during a call with reporters on Monday.
Moderna and Pfizer vaccines use new technology using messenger RNA or mRNA that simply requires a genetic code. The aim of the project is to make vaccines easy to update quickly, without the months of preparation needed to change an influenza vaccine, for example.