What Do We Know About Real-World Effectiveness Of Covid-19 Vaccines Against Delta Variant?

The Delta variant, which is a "variant of concern" according to the World Health Organization (WHO), is not only highly contagious but also spreading around the globe like a wildfire with the potential to become more lethal. While a few weeks ago, the government experts in India said that 90 per cent of the Covid-19 cases were found to be caused by this variant, it became dominant in the United States and caused a dramatic increase in recent Covid-19 cases in the United Kingdom.

During a news conference, Dr Mike Ryan, who is the executive director of the WHO's health emergencies program, said that the Delta Variant has the potential to become more deadly as it is more efficient in the way it transmits from human to human and "it will eventually find those vulnerable individuals who will become severely ill, have to be hospitalised and potentially die". Additionally, he stated that "we can protect those vulnerable people, those front-line workers…and the fact that we haven't, as Director-General [Tedros Adhanom Ghebreyesus] has said, again and again, is a catastrophic moral failure at a global level".

In the United States, as of now, more than 47 per cent of the population is fully vaccinated, while in the case of the United Kingdom, this figure is over 50 per cent. But as per the reports, the vaccination rates have decreased in the US at a time when the county is reporting a surge in Covid-19 cases due to the dominance of the Delta variant. Understanding the issue, American President Joe Biden recently said that to reach more people who have not yet received vaccines, his administration will shift its focus from mass vaccination sites to a smaller and more community-based approach.

But in the UK, the scene is different. In a dramatic rollback of Covid-induced limitations, Prime Minister Boris Johnson has stated that his administration intends to repeal the law requiring masks and social isolation. Johnson's comments came at a time when the country witnessed its highest case count since January this year—on 9 July, the UK recorded over 35,700 new cases.

Covid-19 Vaccines

As per the Public Health England's (PHE) weekly analysis, the ongoing rise in infections has not been accompanied by an increase in hospitalisations or deaths, indicating that both doses of a Covid-19 vaccine provide excellent protection. As reported, though hospitalisations are up somewhat in July due to a large increase in cases, the overall rate of admission is much lower than it was during the pandemic's fatal third wave in the UK.

In another investigation, the PHE discovered that all vaccinations used in the UK—such as Pfizer-BioNTeh, Moderna, Oxford-AstraZeneca and Johnson & Johnson—are equally efficient at avoiding symptomatic disease in most individuals with underlying health conditions. Even if the virus continues to spread in the community, the decrease in hospitalisation demonstrates that immunisations are providing adequate protection to prevent severe infections.

In terms of other Covid-19 vaccines, Sergey Netesov, who is the head of the Novosibirsk State University's Laboratory and corresponding member of the Russian Academy of Sciences (RAS), said that the viral vector and mRNA vaccines, including Russia's Sputnik V, give adequate protection against the new Delta coronavirus variant. He noted that "according to data from the UK, the US and other countries, mRNA and vector vaccines, including our Sputnik V, protect against it [the Delta variant], albeit to a lesser extent, but they do protect against it. They offered 95 per cent protection against the initial strain, and now they give 90 per cent protection against the "Delta variant".

According to a study conducted by the Indian Council of Medical Research-National Institute of Virology (ICMR-NIV), Indian company Bharat Biotech's Covid-19 vaccine Covaxin elicits a higher antibody response against the Beta and Delta strains of the SARS CoV2 virus as compared to post-natural infection. Pragya D Yadav, a scientist at ICMR NIV Pune said: "We assessed the neutralisation of sera from Covid-19 recovered cases post 5-20 weeks of infection and 28 days after two doses of Covaxin against the variants and compared to prototype B.1 (D614G). Covaxin was found to confer significant protection against both the variants".

However, Soumya Swaminathan, the chief scientist at the WHO, told the Financial Times: "Real-world effectiveness studies with a number of vaccines show good protection, especially against severe disease. The most important priority just now is to scale up vaccination coverage in all countries".