Hinting at the fact that to be completely secure and something close to that, one will have to have at least three to four Covid-19 booster shots. The vaccines that are being administered now protect against severe Covid-19, hospitalizations and deaths. But as immunity wanes over time and new, more contagious SARS-CoV-2 variants emerge.
Experts therefore have stressed on the need for a long-term boosting strategy against the contagious SARS-CoV-2.
David R. Martinez, a Postdoctoral Fellow in Epidemiology, University of North Carolina at Chapel Hill, in an interview with news agency PTI has emulated the future of Covid-19 vaccine.
Following include excerpts from the expert’s statements.
Covid-19 booster shots have been formulated to fight against the Covid-19 variant that emerged in late 2019, said the immunologist.
“I’m an immunologist who studies immunity to viruses. I was a part of the teams that helped develop the Moderna and Johnson & Johnson SARS-CoV-2 vaccines, and the monoclonal antibody therapies from Eli Lilly and AstraZeneca,” Martinez clarified.
Martinez said that no one can predict the SARS-CoV-2 variant that will emerge next, but other respiratory viral foes that have troubled humanity for a while can suggest what the future could look like.
Periodic Booster shots may become the norms for people in the foreseeable future as SARS-CoV-2 continues to evolve.
Martinez took up the case of Influenza virus which has now become an endemic in humans and continues to cause recurrent seasonal waves of infection in the population.
The expert therefore also suggested that scientists will have to create newer formulas to keep up with the emergent variants of SARS-CoV-2. The idea of tailor-made annual shots – like the flu vaccine – sounds appealing. The problem is that scientists haven’t yet been able to predict what the next SARS-CoV-2 variant will be with any degree of confidence.
Forecasting Covid-19 based on careful surveillance of Flu outbreaks
Influenza virus surveillance offers a potential model for how SARS-CoV-2 could be tracked over time. Flu viruses have caused several pandemics, including the one in 1918 that killed an estimated 50 million people worldwide. Every year there are seasonal outbreaks of flu, and every year officials encourage the public to get their flu shots.
“While the particulars for influenza and SARS-CoV-2 viruses are different, I think the COVID-19 field should think about adopting similar surveillance systems in the long term. Staying on top of what strains are circulating will help researchers update the SARS-CoV-2 vaccine to match up-to-date coronavirus variants,” said the immunologist.
How SARS-CoV-2 has evolved so far
SARS-CoV-2 faces an evolutionary quandary as it reproduces and spreads from person to person. The virus needs to maintain its ability to get into human cells using its spike protein, while still changing in ways that allow it to evade vaccine immunity.
Vaccines are designed to get your body to recognise a particular spike protein, so the more it changes, the higher the chance that the vaccine will be ineffective against the new variant.
Despite these challenges, SARS-CoV-2 and its variants have successfully evolved to be more transmissible and to better evade people’s immune responses.
Almost like clockwork, the D614G variant emerged in the spring of 2020 and overtook the original SARS-CoV-2 outbreak strain. In late 2020 and early 2021, the alpha variant emerged and dominated transmission. In mid-2021, the delta variant overtook alpha and then dominated transmission until it was displaced by the omicron variant at the end of 2021.
There’s no reason to think this trend won’t continue.
Current booster shots are simply additional doses of the vaccines based on the outbreak SARS-CoV-2 virus strain that has long been extinct. The coronavirus variants have changed a lot from the original virus, which doesn’t bode well for continued vaccine efficacy.
Yes, the dominant SARS-CoV-2 variants in the upcoming fall and winter seasons may look different from the omicron subvariants currently circulating. But an updated booster that more closely resembles today’s omicron subvariants, coupled with the immunity people already have from the first vaccines, will likely offer better protection going forward. It might require less frequent boosting – at least as long as omicron sublineages continue to dominate.
Vaccine makers like Moderna are currently testing their booster candidates in people and evaluating the immune response against newly emerging variants.
Another possibility is to pivot the vaccine booster strategy to include universal coronavirus vaccine approaches that already look promising in animal studies. Researchers are working toward what’s called a universal vaccine which would be effective against multiple strains.
Some focus on chimeric spikes, which fuse parts of the spike of different coronaviruses together in one vaccine, to broaden protective immunity. Others are experimenting with nanoparticle vaccines that get the immune system to focus on the most vulnerable regions within the coronavirus spike.
Science has provided multiple safe and effective vaccines that reduce the risk of severe Covid-19. Reformulating booster strategies, either toward universal-based vaccines or updated boosters, can help steer us out of the Covid-19 pandemic.
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