According to the Indian Council of Medical Research (ICMR)’s second national sero-survey report, 6.6 percent individuals aged above 10 years, had been exposed to the novel coronavirus by August 2020.
As per the sero-survey report: “Of the 29,082 people that were surveyed from August 17 to September 22, 6.6 percent showed evidence of past exposure to SARS-COV-2."
The seroprevalence among individuals aged above 18 years was found to be 7.1 percent; as against this, seroprevalence was found in only 0.73 percent adults in the first sero-survey that was conducted in May.
Frequently Asked Questions
A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.
There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.
Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.
Notably, the second sero-survey was conducted in the same 700 villages and wards across 21 states. However, unlike last time, individuals aged above 10 years were surveyed, acknowledging their risk of contracting the deadly disease as well.
The other finding of the second sero-survey was that SARS-CoV-2 infection prevalence was higher in urban slum (15.6 percent) and non-slum (8.2 percent) areas as compared to rural areas at 4.4 percent.
Meanwhile, Union Health Minister Harsh Vardhan has said that ICMR’s survey confirms that India is far from achieving herd immunity against the novel coronavirus. Therefore, the need to adhere strictly to COVID-19 protocols remains of utmost importance.
Dr Balram Bhargava, Director-General, ICMR, has said: “In light of the upcoming festivities, winter season and mass gathering, inventive containment strategies need to be implemented by the states…. Since a large proportion of the population is still susceptible, prevention fatigue is to be avoided and 5T strategy (Test, Track, Trace, Treat Technology) to be adhered.”
One must note here that antibody tests are not diagnostic tests. These are essentially surveys that help understand the prevalence of an infection in the larger population so that authorities can craft strategies accordingly to fight the disease spread.