Emerging variants of the virus causing Covid-19 have raised concerns that vaccines developed to date will not provide the high level of protection observed in clinical trials. Variants were identified for California, South Africa, Brazil and the United Kingdom.
But not every variant needs a new vaccine, because vaccines produce a broad immune response that will likely cover many mutations. Here’s how to put one together for use with your vaccine.
Detection To face a new variant, you must first detect it. Surveillance is essential, so scientists must be constantly vigilant and engage in international cooperation, as in the case of the influenza virus. Approved vaccine manufacturers – including Pfizer / BioNTech, Moderna and Oxford / AstraZeneca – are looking for ways to improve their vaccines so that they are prepared for any variant.
Comparison Once a cause for concern has been identified, scientists need to check whether the effectiveness of the existing vaccine has decreased significantly. In the case of the variant discovered in Great Britain, the scientists were sure that the vaccines already available worked well against it, but for the one discovered in South Africa the data are much less encouraging.
Change If the vaccine needs to be modified, the technology used in the vaccine determines how quickly and easily the change can be made. For example, mRNA vaccines produced by Pfizer / BioNTech and Moderna are much easier to modify than traditional vaccination technologies.
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Production BioNTech said it can produce a fresh vaccine within six weeks of making a decision. But the Oxford / AstraZeneca team, which uses more traditional viral vector technology, says that while it can produce a new formulation in a few days, it takes much longer to produce. It is expected to have a vaccine designed to address the variant discovered in South Africa ready by autumn.
Trials It is unclear how extensive studies with modified vaccines will be. In the case of influenza vaccines, regulators do not require large-scale studies, but are satisfied with smaller studies to show that they work as well as the original vaccine. This is probably what will be expected from Covid-19 vaccine manufacturers.
Approval The new vaccine will have to be approved by regulators. In the UK, the Medicines and Medicines Regulatory Agency (MHRA) has said it is in talks with vaccine manufacturers about the approval process for a new jab. “We can say at this stage that a full approval process is unlikely to be necessary,” a spokesman said last month. “No vaccine will be authorized for supply in the United Kingdom unless the expected standards of safety, quality and efficacy are met.”