Emerging variants of the virus that causes Covid-19 have raised concerns that vaccines developed so far will not provide the high level of protection seen in clinical trials. Related variants have been identified in California, South Africa, Brazil and the United Kingdom.
But not every variant needs a new vaccine, since vaccines produce a broad immune response that is likely to cover many mutations. Here’s what needs to be done to assess whether a vaccine needs to be adjusted and how to adjust it.
Detection To confront a new variant, you need to detect it first. Surveillance is essential, therefore, scientists need to be constantly vigilant and engage in international cooperation, as they do with the flu virus. Approved vaccine manufacturers – including Pfizer / BioNTech, Moderna and Oxford / AstraZeneca – are looking for ways to improve their vaccines so that they are ready for any variant.
Comparation Once a variant of concern has been identified, scientists need to verify that the effectiveness of the existing vaccine has significantly decreased. In the case of the variant discovered in the UK, scientists were confident that the vaccines already available worked well against it, but for the discovery in South Africa the data is much less encouraging.
Modification If a vaccine adjustment is necessary, the technology used in the vaccine determines how quickly and easily the change can be made. For example, mRNA vaccines made by Pfizer / BioNTech and Moderna are much easier to adjust than traditional vaccine technologies.
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Production BioNTech said it could produce a new vaccine within six weeks after a decision was made. But the Oxford / AstraZeneca team, which uses more traditional viral vector technology, says that although it can make a new formulation in days, it takes much longer to produce. She hopes to have a vaccine designed to combat the variant discovered in South Africa ready in the fall.
Essay How extensive the testing of modified vaccines will need to be is unclear. In the case of flu vaccines, regulators do not require large-scale testing, but instead are satisfied with smaller studies to show that they work as well as the original vaccine. This is probably what is expected of vaccine manufacturers Covid-19.
Approval The new vaccine will need to be approved by regulators. In the UK, the Medicines and Healthcare Products Regulatory Agency (MHRA) said it is in talks with vaccine manufacturers about the process of approving a new jab. “We can say at this stage that a complete new approval process is unlikely to be necessary,” said a spokesman last month. “No vaccine will be authorized for delivery in the UK unless the expected standards for safety, quality and efficacy are met.”