A missing science pillar in the COVID response

The article deals with the emerging trends from the surge in Covid cases and suggests a data-driven policy approach followed by a national vaccination program to deal with the challenge.

Surge in Covid cases

• Recently, there has been a sharp increase in new cases and deaths from the disease.
• Maharashtra seems to be particularly affected, but nearly all States are reporting increases.
• The epidemiology of COVID-19 is poorly understood.
• But some early understanding of the transmission of the virus can enable a more effective science-driven response.

Variant of virus could be behind the spread

• The surge is probably driven by variants from the original, as variants worldwide comprise much of the current wave.
•  Evolutionary theory would expect SARS-CoV-2, the virus that causes COVID-19, to mutate to become more transmissible.
• However, the expected concomitant decrease in lethality has not yet been documented.
• Anecdotal reports that the current surge is occurring more in younger adults and accompanied by unusual symptoms also support the idea that variants are responsible.
• Direct evidence is needed from genetic sequencing of the virus.

No herd immunity

• Various serosurveys have consistently found that half or more of tested urban populations have antibodies to the virus.
• However, this high level of infection is not the same as a markedly reduced level of transmission, which is what is required for herd immunity.
• Notions of herd immunity do not fully capture the fact that for largely unknown reasons, viral transmission is cyclical.
• Much of the infection in India might well be mild, with less durable immune protection than induced by vaccination.
• Asymptomatic infection is more commonly reported in Indian serosurveys, exceeding 90% in some, in contrast to high-income countries, where about one-third of infections report as asymptomatic.
• Milder infection might well also correlate with lower severity of clinical illness, helping to explain the Indian paradox of widespread transmission but with low mortality rates.

Policy must be data-driven

• Theories or mathematical models are hugely uncertain, particularly early on in the epidemic.
• A better understanding of the unique patterns of Indian viral transmission has a few pillars, which can be achieved quickly.
• First, collection of anonymised demographic and risk details like age, sex, travel, contact with other COVID-19 patients, existing chronic conditions, current smoking on all positive cases on a central website in each State remains a priority.
• Second, greatly expanded sequencing of the viral genome is needed from many parts of India, which can be achieved by re-programming sequencing capacity in Indian academic and commercial laboratories.
• Third, far better reporting of COVID-19 deaths is needed.
• Daily or weekly reporting of the total death counts by age and sex by each municipality would help track if there is a spike in presumed COVID-19 deaths.
• Fourth, the Indian Council of Medical Research’s national serosurvey had design limitations such that it probably underestimated the true national prevalence.
• A far larger and better set of serial surveys is required.
• Finally, we need to understand better why some populations are not affected.

Counter the inequality in vaccination

• Affluent and connected urban elites of India are vaccinating quickly, but the poorer and less educated Indians are being left behind.
• Vaccination campaigns need to reach the poor adults over age 45, without having to prove anything other than approximate age.
• Follow-up studies among the vaccinated can establish the durability of protection, and, ideally, reduction in transmission.
• Similarly, India must capture and report data on who is vaccinated, including by education or wealth levels.
• The poor cannot be left in the dark.

Prepare for future pandemics through adult vaccination plan

• COVID-19 could well turn into a seasonal challenge and thus, the central government should actively consider launching a national adult vaccination programme.
• The Disease Control Priorities Project estimates an adult national programme would cost about ₹250 per Indian per year to cover routine annual flu vaccination, five-yearly pneumococcal vaccines, HPV vaccines for adolescent girls and tetanus for expectant mothers.
• Per year, vaccines for one billion adults might save about 200,000 lives from the targeted diseases.
• Indeed, we might already be in the era where major zoonotic diseases are not once-a-century events, but once a decade.
• Thus, adult and child vaccination programmes are essential to prepare for future pandemics.

Conclusion

The resurgence of COVID-19 presents a major challenge for governments, yet the best hope is to rapidly expand epidemiological evidence, share it with the public and build confidence that the vaccination programme will benefit all Indians.