A few words from article on potential vaccine efficacy for new variants

Updated: Jan 22

Here is a AP news article reporting on a new paper presenting results investigating how the mutations underlying some of the recently reported variants in the UK, South Africa, and Brazil affect the immune response to SARS-CoV-2, and in particular with respect to the Moderna and Pfizer/BioNTech vaccines.


This is a good article talking about concern about how some of the mutations underlying reported new variants (the South African one in particular) might affect vaccine effectiveness.


My UPenn colleague John Wherry, an immunology expert, is interviewed as part of the article, and he highlights that there will still be a good level of protection, but that new variants can introduce mutations that start eroding the immune response in both those who have recovered from infections as well as from the vaccines.


He highlights that the two key factors are to (1) get vaccines distributed as fast as possible and (2) remain vigilant to slow transmission levels of the virus.


Allowing fast spread like we have (especially in the USA) contributes more opportunities for mutations to emerge and raises the likelihood of immune-resistant variants to emerge. Also, the faster we can get vaccines distributed, the faster we can counteract this and prevent a further refinement of the virus that might make the vaccines less effective.


Two bits of good news that should keep us from overly worrying about the potential of new variants to escape immune response:

  1. A lot of the data showing immune escape, e.g. for the E484K mutation in the South African variant, are based on exposure to monoclonal antibodies such as used in treatments. Vaccines generate polyclonal antibody response that is much more robust than these, so even for mutations that can completely elude monoclonal antibody response it is likely that the vaccines will still have a degree of efficacy.

  2. One of the key features of the mRNA vaccines is that they can be customized/adapted for new variants in practically real time -- given a sequence the mRNA for the vaccine can be quickly determined and can be assessed and ready to go in 6 weeks. Give the same substrate and buffers, the only difference will be a small part of the mRNA sequence, and so it should be possible to expedite review of any updated vaccines, such as what is done for flu vaccines.

So don't lose heart, but the emergence of these variants should highlight what we should be already doing: disseminating vaccines as efficiently as possible and continuing to take the precautions like avoiding crowded indoor places, distancing, and mask wearing that we know reduce viral transmission -- that these are also important in trying to get the pandemic under control before variants more troublesome to our immune response have a chance to evolve and be selected.



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