The number of daily new COVID cases have dropped in India. The festival season, which includes Durga Puja and Diwali, where large groups of Indians gather, in cases. Epidemiological modellers had a third wave peaking during October and November.
Daily new cases have of more than 400,000 cases per day in May 2021 to currently below .
And while antibody tests might give us a clue as to why, we can’t get complacent about vaccination rates.
Signals From Recent Antibody Tests
In India, “serosurveys” have been regularly conducted since the pandemic began. This is where blood is tested from large numbers of people to check for the presence of COVID antibodies.
The in July reported 67.6 percent of people across India had COVID antibodies present, providing them with a level of immunity against the virus. At that time, 24.8 percent of people were immunised with a single dose of vaccine and 13 percent were fully vaccinated. This means a large proportion of those with antibodies had actually been infected with COVID.
Delhi reported in October, including 80 percent of children. Some 95.3 percent of those immunised with the Indian version of the Astrazeneca vaccine Covishield had developed antibodies, as did 93 percent of those who received India’s own vaccine, Covaxin.
The state of Haryana’s found antibodies in 76.3 percent of adults, upwards of 70 percent among children, and negligible difference between urban and rural populations.
Kerala had the in the fourth national serosurvey in July, but in October it had risen to among the general population and 85.3 percent among residents of urban slums.
What Does This Mean for a 'Third Wave' in India?
A third wave in India is an unlikely scenario with these high levels of antibodies, and vaccination levels continuing to rise.
It’s now recognised those who become naturally infected with COVID and recover before vaccination than those who only have antibodies from vaccination. This is referred to as “hybrid immunity” – those with previous SARS-CoV-2 infection mount to the COVID vaccines.
The in the US notes that both the fully vaccinated individuals and previously infected groups have a low risk of subsequent infection for at least six months.
in India reflect the seroprevalence during the third week of June 2021; the Delta-led second wave had bottomed out at that time. Though about 30 percent of the population remained susceptible, subsequent serosurveys and an absence of any post-festival surge confirm continuing high levels of protection.
“Patchwork vaccination” areas, where there are pockets of low coverage of vaccination among areas with high levels of coverage, run the risk of small outbreaks, but are unlikely to be large enough to be of any major epidemiological concern.
With high seropositivity among adults, many of the new cases can now be expected among children, particularly with the reopening of educational institutions. But high levels of immunisation among teachers () and the that reopening schools has not been associated with significant increases in community transmission, are reassuring.
The WHO’s chief scientist that India seems to be “entering some stage of endemicity”. refers to the constant presence or usual prevalence of a disease in a population within a geographic area, where disease spread and rates are predictable.
Could a new variant, such as the Delta Plus subvariant in April 2021 threaten the current relative stability? While it has been said it might be about than the Delta variant, the suggests it has not yet been able to establish any dominance over Delta.
Is Vaccination on Track?
Of India’s 1.4 billion people, are fully vaccinated and 54.9 percent have received at least one dose so far. But have been vaccinated compared to men and show tribal and rural districts continue to lag.
There are two current targets: achieving 90 percent coverage of the first dose by the and timely administration of the second dose. While the first is likely to be achieved, there are widespread reports of . A to encourage people to complete the schedule.
Delivering the billion plus doses has convincingly demonstrated vaccine confidence. But convincing people to take a vaccine when for many it seems like the risk has passed is a difficult task. Prior infection-induced immunity protects against reinfection but this acquired immunity wanes over time. Hence the recommendation for COVID vaccination for all eligible persons, including those who have been previously infected.
Districts with relatively low vaccine coverage require greater outreach efforts to reduce prevailing inequities. India’s immunisation programme has demonstrated its strengths in polio eradication and measles-rubella elimination campaigns. We need to borrow some of those techniques to ensure all Indians are protected against COVID.
(Rajib Dasgupta is the Chairperson, Centre of Social Medicine and Community Health at the Jawaharlal Nehru University)
(This is an opinion piece and the views expressed above are the author’s own. The Quint neither endorses nor is responsible for them. This article was originally published on The Conversation. Read the original article here.)