Although there is no evidence that people immunized with any of the vaccines have less protection against the variants, both companies said they have begun looking for ways to explain the evolution of the mutations.
Particularly worrying is variant B.1.351, first seen in South Africa. It carries a mutation that helps prevent the body’s immune response to infection. Variant B.1.1.7, first seen in the UK, is also a cause for concern, as its mutations appear to make it more transmissible, so it spreads better and can also cause more severe diseases.
Researchers are also finding variants in the US that have developed mutations that help them evade the immune system.
Pfizer and its partner BioNTech said Thursday that they have begun testing how well it could protect against the addition of a third dose of the authorized vaccine against the new variants.
The study will look at the safety and immune response of a booster dose in up to 144 participants in the previous US Phase 1 study, including a subset of adults up to the age of 85 years. It will also involve testing how well their antibodies are able to neutralize the “strains 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 dosage would be identical to what is currently allowed: 30 micrograms.
“This booster study is essential to understanding the safety of a third dose and its effectiveness against circulating strains,” said Dr. Albert Bourla, CEO of Pfizer, in a statement.
Separately, Pfizer and BioNTech are also in ongoing discussions with regulators on the potential testing of a modified vaccine to protect against the variants involved in a phase 1/2 study.
However, Bourla noted that the companies have not yet seen convincing evidence that the variants are resistant to his vaccine, although they are taking steps to be prepared.
Moderna said late Wednesday that it had produced an updated version of the Covid-19 vaccine to help it fight the B.1.351 variant first seen in South Africa. The initial doses were sent to the National Institutes of Health for a clinical study.
The new vaccine, called mRNA-1273.351, will be evaluated as a booster vaccine 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 would 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 third lower dose of the current Covid-19 vaccine can boost immunity to worries about coronavirus, with some study participants already receiving the third dose.
“We are moving quickly to test vaccine updates that address emerging variants of the virus in the clinic. Moderna is committed to doing as many updates to our vaccine as possible until the pandemic is under control. We hope to demonstrate that booster doses, if necessary, it can be done at lower doses, which will allow us to deliver much more doses to the global community at the end of 2021 and 2022, if needed, ”Stephane Bancel, CEO of Moderna, said in a statement.
Moderna did not say how long the studies are expected to take or when the new vaccine will be available, if authorized. The current vaccine uses two doses of 100 micrograms spaced about a month apart. The new booster doses are assessed at half of that level and lower.
On Monday, the US Food and Drug Administration announced new guidelines that would streamline and speed up the vaccine update process to target variants. An agency official estimated that this could involve several hundred people and could take several months.
“It will be in the order of a few hundred people in terms of size and we would expect this to take several months,” said Dr. Peter Marks, director of the FDA’s Center for Biological Assessment and Research, during a call Monday with reporters.
Both the Moderna vaccine and the Pfizer vaccine use a new technology that uses messenger RNA or mRNA that simply requires a genetic code. The design is meant to make vaccines easy to update quickly, without the months of preparation needed to change a flu vaccine, for example.