Serosurveys and seroprevalance
The Indian Council of Medical Research (ICMR) has conducted four serosurveys in India so far, the latest of which was done between June 14 and July 6 and stated that two-thirds of Indians have developed antibodies against Covid-19, but 40 crore are still vulnerable. It also stated 67.6 per cent of India's population aged above six years has developed antibodies for Covid-19.
What are serology and seroprevalence?
- Serology is the study of antibodies in blood serum. Antibodies are part of the human body's immune response to an infection or virus, like SARS-CoV-2. Covid-19's antibodies are detectable usually within the first few weeks after infection.
- The presence of antibodies in a person means they were infected with the virus, irrespective of whether they had severe, mild, or no symptoms.
- Seroprevalence is determined by a study conducted to measure the extent of an infection, measured by level of antibodies, in a population.
- The percentage of individuals in a population who have antibodies to infection is called seroprevalence.
- With a new virus, including Covid-19, initial seroprevalence is assumed to be low as the virus has not circulated before.
- A positive result from a serology test may mean that a person was previously infected with the virus.
- This testing helps determine the size of the outbreak of a disease or the extent to which a certain population has been infected or exposed to an infection.
- It helps capture unrecognised cases not detected during routine surveillance.