A clamour for Covid-19 booster shots juxtaposed with newly emerging variants of the novel coronanvirus have prompted discussions over whether available vaccines can provide long-lasting protection.
A special envoy to World Health Organisation (WHO) has said variants that can evade Covid vaccines are increasingly likely as many parts of the world remain unprotected, and that rich countries must wait for others to catch up before they start administering booster doses, according to a report by Bloomberg.
In an interview to Bloomberg Television, Dr David Nabarro was quoted as saying, “Variants that can beat the protection offered by vaccines are bound to emerge all over the world in the coming months and years. This is an ongoing battle, and we need to work together.”
As countries like UK prepare to give a booster dose to already vaccinated people, a review published in The Lancet on Monday also said vaccine efficacy against severe Covid-19, even for the delta variant, was so high that booster doses were not appropriate at this stage in the pandemic. The review was published by an international group of scientists. The expert panel also includes scientists from WHO and the US Food and Drug Administration.
The WHO has repeatedly discouraged high-income countries from using booster shots and has repeatedly said high rates of vaccination can help prevent hospitalisations and deaths. However, the virus can continue to spread where vaccination rates are low that can pose a whole new problem in the form of new variants.
Dr Nabarro also reiterated the same views and called for prioritising “global needs over national agenda”. “This world is struggling with a dangerous virus that is constantly evolving and new variants are emerging, and there will be more,” he said. “I think this virus is most definitely here to stay for the foreseeable future,” he was quoted as saying.
In India, too, top virologist Dr Gagandeep Kang last month said Covid vaccines were working against the delta variant and people should not rush for booster shots. In an exclusive interview to CNBC, she said the third dose does help but does not guarantee protection.
The Biden administration in the US had allowed booster shots for immunocompromised. It has also said it planned to make vaccine booster shots widely available to all Americans starting on September 20.
Continued spread of the virus has spawned mutations that are better equipped to infect humans and evade vaccine protection. In an article titled ‘New variants of coronavirus: What you should know’ on the website of Johns Hopkins Medicine, Dr Stuart Ray, vice-chair of medicine for data integrity and analytics, said, “There is evidence from laboratory studies that some immune responses driven by current vaccines could be less effective against some of these variants.”
Dr Ray further said: “People who have received the vaccines should…continue with coronavirus safety precautions to reduce the risk of infection, such as mask wearing, physical distancing and hand hygiene.”
Scientists for now are focused on the highly virulent delta variant that is still dominant.
“Delta is showing us that we cannot sit on our laurels and remain diligent…to stop this virus from circulating as much as we can,” said Dr Maria Van Kerkhove, WHO’s technical lead for Covid-19.
First detected in India, the delta variant is the most worrisome and has struck unvaccinated populations in many countries, proving capable of infecting a higher proportion of vaccinated people as well.
The one to watch, however, is the Mu variant. Formerly known as B.1.621, it was first identified in Colombia in January. On August 30, the WHO designated it as a “variant of interest”. According to the WHO, Mu has caused some larger outbreaks in South America and Europe.
(With agency inputs)