Researchers keeping an eye on changes in the genetic behaviour of SARS-CoV-2, the virus that causes COVID-19, have found that booster vaccines will be necessary to beat the pandemic, since permanent immunity may not be assured.
Vaccine boosters have the dual impact of boosting immunity against the original COVID-19 virus, as well as provide methods to overcome the emerging variants that could render existing vaccines ineffective.
Sharon Peacock, head of COVID-19 Genomics UK (COG-UK), an effort to sequence the virus’ genome, said changes that make the virus more transmissible, with a higher ability to evade immunity means regular booster shots will be needed to fight future variants.
The novel coronavirus mutates about once every two weeks.
“We already are tweaking the vaccines to deal with what the virus is doing in terms of evolution – so there are variants arising that have a combination of increased transmissibility and an ability to partially evade our immune response,” Peacock said in a Reuters report on Monday.
The COVID-19 genomic consortium headed by Peacock is one of the world’s largest databases for the virus, with 346,713 genomes of the virus sequenced out of about 709,000 globally.
The rise of new variants of COVID-19 almost displaced vaccination as the main global exit strategy out of the pandemic. It has sent vaccine manufacturers back to the drawing board as AstraZeneca, for instance, continues to face barriers including the South African variant resistance to its vaccine efficacy and concerns over safety.
It forced Pfizer/BioNTech and Moderna pharmaceutical companies to exercise extra caution and rethink their approach for the future of the pandemic, even though their vaccines prove effective against the world’s most disturbing strain, B1351 from South Africa.
Moderna Inc. towards February end completed manufacturing of clinical trial material for its variant-specific vaccine candidate against B1351.
The company said it would evaluate booster doses of vaccine to increase neutralising immunity against the variant, at the same time updating its strategy for addressing variants of concern.
As of March 10, it announced that the first participants have been dosed with modified COVID-19 vaccines, designed to address the potential need for booster vaccine, in an amendment to an on-going phase 2 clinical study.
Pfizer and BioNTech also announced in late February, that they were developing a new vaccine targeting the B1351 variant.
Similarly, the University of Oxford has started developing a second-generation version of its vaccine to target Covid-19 variants with mutations similar to B1351.
Sarah Gilbert, University of Oxford, professor of vaccinology in an interview said efforts were underway to develop a new generation of vaccines that will allow protection to be redirected to emerging variants as booster jabs, if it turns out necessary.
The university is working with AstraZeneca to optimise the pipeline required for a strain change. According to Eric Yager, an associate professor of microbiology at Albany College of Pharmacy and Health Sciences, New York, vaccine boosters can help tackle the threat of emerging variants by providing individuals immunity against known variants.
“Boosters have been used successfully with seasonal flu vaccines. Receiving the flu vaccine each year can work like a booster to enhance immunity against that flu strain,” Yager said.
