Concerned about new variants of the virus that causes COVID-19, the US Food and Drug Administration announced on Thursday that is developing guidelines to help manufacturers of vaccines, drugs and tests adapt.
Existing vaccines, treatments and tests still work well, emphasized FDA acting commissioner Janet Woodcock. But now is the time to prepare for a future when it may not.
“We must prepare for all eventualities,” she said in a conference call with reporters.
In the coming weeks, the FDA will provide preliminary guidance to manufacturers on how to adapt their products as needed, said Woodcock. Feedback from companies and others will help to refine this orientation.
Concern has grown in recent weeks over the variants of the SARS-CoV-2 virus that causes COVID-19, some of which appear to be more infectious.
At least one, identified for the first time in South Africa, has made Novavax and AstraZeneca-Oxford vaccines less effective in that country, while still preventing serious illness and death.
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The vaccines from Moderna and Pfizer-BioNTech also resisted when tested in Petri dishes against a new variant first seen in the UK and now spreading rapidly across the U.S. Moderna’s vaccine did not do so well against the variant seen for the first time in South Africa, although it is likely still offered some protection.
Diagnostic PCR tests, the gold standard for detecting SARS-CoV-2 infection, also appear to continue to work well, said Woodcock, although they are relatively easy to update if viral mutations become more problematic.
With treatments, the main concern is with monoclonal antibodies, which are used to prevent disease progression in high-risk patients. These drugs are extremely targeted, so if the area of the virus they aim to change, they can become ineffective, said Woodcock.
The companies that manufacture monoclonal products are already responding with the development of combinations of drugs that target several areas. Eli Lilly, which makes an authorized monoclonal antibody, recently announced that it hoped to add a second to ensure that the treatment remains effective despite changes in the virus.
With a vaccine, the main goal is to prevent serious illness and death, and current vaccines still protect against it, said Dr. Anthony Fauci, the country’s leading infectious disease doctor.
To prevent the evolution of even more dangerous variants, it is crucial to wear a mask, avoid crowds indoors, wash your hands frequently and be vaccinated when possible, Fauci told a news conference at the White House earlier this week.
“Viruses cannot mutate if they don’t replicate,” he said. “And if you interrupt your replication by vaccinating widely and not giving the virus an open playing field to continue to respond to the pressures you put on it, you won’t get mutations.”
What a new vaccine might look like
Although current vaccines appear to have at least some effectiveness against known variants, there is no doubt that the time will come when a new or adjusted one will be needed.
All viruses mutate. The virus that causes COVID-19 has mutated quite slowly over the past year, evolving only a handful of important new variants – not yet different enough to be scientifically considered new strains.
The flu, on the other hand, evolves so quickly that new vaccines are needed each year, each of which targets three or four strains.
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It is too early to know whether people will need a booster injection every year or two or five to prevent COVID-19 and how this vaccine may need to be adapted as the SARS-CoV-2 virus changes.
All five vaccines that the United States government contracted to buy target the “peak” protein on the surface of the SARS-CoV-2 virus. Mutations in this protein in the South African variant are believed to be behind the reduced effectiveness of the vaccine.
“What this is telling us is that we need to be prepared,” said Dr. Jesse Goodman, a senior scholar at the O’Neill Institute for National and Global Health Legislation in Georgetown and a former FDA chief scientist. “As this preparation will take time, the time to start is now.”
Several open-ended questions will make the process more challenging.
First, unlike a well-known illness like the flu, it is unclear with COVID-19 which levels of antibodies in the blood are sufficient to provide protection. This means that it is difficult to know whether someone is adequately protected until they become ill or not.
Researchers are now looking for so-called protective immune correlates that can be used to assess the effectiveness of a vaccine.
And while the variants known today do not pose a sufficient threat to vaccines, treatments or diagnostics, it will be difficult to predict which variants pose the greatest threats, said Woodcock.
Some may escape vaccines, treatments and diagnostics, but they are not widespread in the United States to pose a problem.
Others may spread widely, but they are not so worrying.
What is the moment?
It is not exactly clear how long it would take to make a vaccine that addresses a new variant, or several, because it has never been done before.
All of the COVID-19 vaccines that have been used in people so far have been developed in less than a year. Designing a new version should take much less time, vaccine manufacturers said.
The technology behind the Pfizer-BioNTech and Moderna vaccines, in particular, allows for rapid changes, with only one adjustment to the model used to do so.
In a prepared statement, Pfizer said that flexibility is one of the main advantages of its mRNA platform compared to older vaccine technologies.
“This flexibility includes the ability to change the sequence of RNA in the vaccine to cover new strains of the virus,” says the statement. “If ever there was one that was not well covered by the current vaccine, the updated vaccine could be administered as a booster.”
Pfizer CEO Albert Bourla said last week that the company “is already laying the groundwork to respond quickly if a variant of SARS-CoV-2 shows evidence of escaping immunity by our vaccine,” according to the statement.
Companies and regulators still need to define the process that would be followed to vary vaccines.
“We need to generate data that gives confidence that any updated vaccine is safe and effective,” said Bourla in the statement.
There are several ways in which companies can change their COVID-19 vaccines to deal with new variants.
First, as the CEO of Moderna mentioned, they could add a booster injection geared specifically to a specific variant. This may require a third low-dose injection for people who have already received two doses of Moderna’s vaccine.
People who have not yet been vaccinated can receive an injection that addresses several variants at the same time, such as the annual flu vaccine.
The best option, Fauci said in a lecture this week at the New York Academy of Sciences, would be to develop a “universal vaccine against SARS-CoV-2 to deal with the inevitable evolution of mutations.”
“But in the long run,” he said, “we would also like to develop a universal vaccine against all coronaviruses (the family to which SARS-CoV2 belongs), since we have already experienced three separate pandemics (coronaviruses), one of which is still we are right in the middle of. “
Contact Karen Weintraub at [email protected].
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This article was originally published in USA TODAY: FDA announces plan to draft guidelines for handling COVID-19 variants