Delhi seems to be achieving herd immunity as around 25 percent of the city's population has been exposed to Covid-19, study says.
According to the study conducted from June 27 to July 10 by the National Center for Disease Control (NCDC) in collaboration with the Delhi government in India,a large number of infected people remains asymptomatic, reports India Times.
Herd Immunity has been described as one of the key factors if we are to win the battle against Covid-19.
It occurs when a large percentage of a population becomes immune to an infection, thus making it potentially less dangerous.
While it is mostly achieved through mass vaccinations, a vaccine for Covid-19 is still months or even years away.
Another way to achieve Herd Immunity is when a large section of the population is exposed to the infection and naturally develops antibodies against it.
According to the Union Health Ministry, 23.48 per cent of the people in Delhi have been affected by Covid-19.
The result of the sero-prevalence study in Delhi has found that a large number of people have infected by the virus.
A sero-survey involves testing of blood serum of individuals to check for the prevalence of antibodies against an infection.
"The results of the sero-prevalence study show that on an average, across Delhi, the prevalence of IgG antibodies is 23.48 per cent. The study also indicates that a large number of infected persons remain asymptomatic," the ministry said in a statement.
"This implies that nearly six months into the epidemic, only 23.48 pc of the people are affected in Delhi, which has several pockets of dense population," said the ministry, attributing it to efforts taken by the government to prevent the spread of infection including lockdown, containment and surveillance measures, including contact tracing and tracking, as well as citizen's compliance to COVID appropriate behaviours.
It, however, said that a significant proportion of the population is still vulnerable and therefore, the containment measures need to continue with the same rigour.
Non-pharmacological interventions such as physical distancing, use of face mask/cover, hand hygiene, cough etiquette and avoidance of crowded places etc., must be followed strictly, it underlined.
For all the 11 districts of Delhi, survey teams were formed. Blood samples were collected from selected individuals after taking written informed consent and then their sera were tested for IgG antibodies and infection using COVID KAVACH ELISA approved by the Indian Council for Medical Research.
It is one of the largest sero-prevalence studies conducted in the country using the ELISA testing.
A total of 21,387 samples were collected as per lab standards and were tested.
The tests help in identification of presence of antibodies in the general population. The test performed is not a diagnostic test but only provides information about past infection due to SARSCoV-2 in individuals who test positive, the ministry said.