With more than 100 countries across the globe affected by the highly transmissible and more virulent Delta variant of Covid-19, a question that remains is who is protected against the strain. A recent study conducted by the Indian Council of Medical Research (ICMR) and National Institute of Virology (NIV) Pune, has found that those who recovered from the virus and have been administered with both doses of Covishield have higher immunity against the Delta variant.
For the study titled 'Neutralization of Delta Variant with Sera of Covishield Vaccines and Covid-19 Recovered Vaccinated Individuals,' neutralising antibody (NAb) responses of three types of people were accessed -
1. Individuals who were inoculated with two doses of Covishield.
2. Coronavirus-recovered individuals who were administered both doses of Covishield
3. Covid-19 recovered individuals who had contracted breakthrough infections such as Kappa and the Delta variants.
The study findings discovered that Covid-19 recovered individuals and the breakthrough cases had "relatively higher neutralising responses against the Delta variant in comparison to the participants who administered either one or two doses of Covishield."
A comparative assessment of Covishield vaccinated individuals' sera (n=116) in different categories was performed against the prototype strain B.1 (D614G) and the Delta variant of Covid-19. Moreover, under this study, sera was classified into five categories – 1. One dose (n=31), 2. Two doses (n=31), 3. Covid-19 recovered and inoculated with one vaccine dose (n=15), 4. Covid-19 recovered and vaccinated with both jabs (n=19), and 5. Breakthrough coronavirus cases (n=20).
The sera from the first four categories were collected from the individuals after four weeks of their vaccination. On the other hand, the sera from the participants of the "breakthrough cases" of coronavirus category was sampled two weeks following their inoculation, the study report stated.
Findings revealed that NAbs in individuals with breakthrough cases, and those recovered from Covid-19, with single or both doses of Covishield, had relatively higher protection against the Delta variant of the virus as opposed to those who only took at least one or both doses of vaccine.
Notably, it is a test that gauges the presence and number of antibodies in a person's blood.
Meanwhile, in a recent ICMR study, it has been found that India's first indigenous anti-Covid-19 vaccine Covaxin, is effective against the Delta Plus variant of the virus – a subtype of the Delta variant. Last week, Union science and technology minister Jitendra Singh said that as many as 70 cases of Delta Plus variant were detected by INSACOG, a cluster of labs that do genome sequencing.
The World Health Organisation (WHO) also warned against the rapidly spreading Delta variant across the globe, and said that it is expected to become the dominant variant amongst all other variants of concern.