The U.S. pharmaceutical company Moderna says it plans to begin human studies of a booster shot for its vaccine to boost protection against a more transmissible variant of the virus.
Even at lower antibody levels, the existing vaccine should offer protection against the strain first seen in South Africa, Moderna said Monday. But a test showed Moderna’s existing vaccine may be less potent against that strain, Reuters reported.
As of Thursday, the B.C. Centre of Disease Control identified three cases of the South African variant, officially named 501Y.V2. The source is unknown as no travel outside Canada has been associated with the cases.
The Centre also identified six confirmed cases of variant B.1.1.7 which was first reported in December in the United Kingdom. Four of the infected B.C. people reported travel outside of the country, while the two other were close contacts, the Centre said.
Postmedia talked to Horacio Bach , an infectious disease specialist who works in the University of B.C.’s faculty of medicine. He’s manager of antibody engineering at the Jack Bell Centre.
Q: What is a COVID-19 variant?
A: Viruses are mutating and changing all the time. If the sequence is beneficial, the virus will continue. A variant can be more transmissible and lead to faster infection. Or it can be that the mutation means the way it’s changed doesn’t lead to infection in the host and it disappears. The mutation can also be what we call nonsense. It doesn’t do anything and doesn’t affect its transmission.
Q: Why are variants important?
A: Variants can happen anywhere. It’s random. That’s why it’s important to reduce transmission as fast as possible. When the virus doesn’t have enough people or hosts to infect, the probability of mutations goes down.
That’s why it is very important to keep the virus at low levels. The fewer people you have unvaccinated, the greater the probability your community will be stronger and you’ll have fewer cases where the virus can infect other people.
Q: What does it mean to develop a booster shot for a vaccine?
A: They’re saying that the variant from South Africa probably may not be recognized by the antibodies created by the vaccine. There are a lot of studies are going on so we don’t know exactly why that’s happening.Preliminary data indicates that antibodies to the vaccine don’t react properly with this variant. We may need to have a booster now with a new vaccine but using the genetic sequence of the variant.
For Moderna and Pfizer BioNTech it is very easy to change the genetic sequence in a sequencer. (A sequencer is a scientific instrument that automates the DNA sequencing process.) It’s much faster than the traditional way.
Q: What do you think will happen with vaccines?
A: I wouldn’t be surprised that in future we have a mix of vaccines for different variants like we do with human papillomavirus. (Three vaccines are used to prevent most of the cancers caused by HPV.) There may be so many variants that we will need to think about mixing different vaccines that target each variant as we have with the flu vaccine.
Horacio Bach is an adjunct professor, division of infectious diseases at UBC.
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Source: VANCOUVER SUN