Think Tank

Covid-19 and the Way Forward: An Epidemiologist’s View

Dr Prabhat Jha, University of Toronto Chair in Disease Control and Founding Director, Centre for Global Health Research, St Michael’s Hospital
India’s fierce second wave of Covid-19 infections in mid-2021 instilled fears about a third wave. Compared to the first wave, which peaked in mid-to-late 2020 and was mostly an urban phenomenon, the second affected rural areas equally. Looking ahead, India will need to be better prepared for future outbreaks, including by ramping up its vaccination drive and by leveraging the available data on infections, particularly among the vaccinated. At a recent all-Forum webinar, epidemiologist Dr Prabhat Jha, of the University of Toronto, took stock of India’s present situation and the strategies it should adopt going forward.

Several unknowns made it hard to make accurate predictions

Shooting in the dark

At the onset of the pandemic in India last March, there was very limited information on the virus. Experts relied on two key data-points – the reproduction number (number of people infected by each infected person) and the case fatality ratio (percentage of deaths among the infected) – to try and predict the likely course Covid-19 would take and the damage it might cause. There was uncertainty about questions such as the number of undetected cases and even whether asymptomatic patients could transmit the disease. To date, Covid-19 continues to be compared to the catastrophic 1918-19 Spanish Flu but the reality is that, as a share of the population, the number of deaths is much lower than a century ago.

The mystery of India’s ‘lower’ death rates

One of the big mysteries last year was why India’s reported death rates were so much lower than those in other countries. Some attributed this to immunology: with most Indians being exposed from early on to other viruses, including measles, it was suspected that they may possess an inherent resistance to the virus. This theory was, however, largely disproved during the second wave.

Multiple peaks in some parts of India, high rates of infection, many asymptomatic cases…

India is more ‘normal’ than many had first thought

A major study (~450,000 self-referred patients) that was conducted during/after the first wave, covering the July-December 2020 period, threw up some significant results:

  • Whereas India’s first wave ‘peaked’ in September 2020 in terms of the number of reported cases, seropositivity rates only peaked in December, indicating that most of those who were infected were asymptomatic.
  • The fastest growth of Covid-19 seropositive deaths was among younger adults, indicating that they were contributing the most to transmission.
  • There were huge variations across India in terms of infection and mortality patterns. Cities like Chennai and Pune saw a single peak, in July and August respectively, while Delhi saw two peaks – in June and then in September.
  • Roughly 40-50% of the urban population was infected during the first wave.

Unofficial data is better at gauging the true mortality costs of Covid-19

Getting a truer picture of Covid deaths…

Globally, there has been a surge in ‘excess deaths’ attributable to Covid-19. The official figures would suggest that India has managed to buck this trend – but this is mainly because mortality is vastly under-reported here. Even in urban India, out of 10 million deaths each year, only 7 million are registered and just 1.3 million come with a proper death certificate. However, it is possible to arrive at a more accurate estimate of excess deaths using other sources. For instance, a large-scale household survey – which asks respondents whether any member of the family has died in the last 4 months – reveals that the number of deaths more than doubled between 2019 and 2021. Most of these deaths were on account of Covid-19.

The real numbers are 7-8x higher than official data would suggest

On the basis of such studies, it has been estimated that India saw 2.7-3.4 million excess, Covid-related deaths, with the bulk of these occurring during the second wave in 2021. Cumulatively, this is 7-8 times higher than the official figures. The over-50s accounted for most of these excess deaths but among younger age groups, women had slightly higher mortality rates than men.

Covid-19 is fast becoming a disease of the unvaccinated

…and preparing for a third wave

Worldwide data indicates a strong correlation between vaccination and reduced infection rates. Contrary to popular belief, nearly all vaccines – especially the vector and inactivated types – have proven highly effective in bringing down infections, even with the fast-multiplying Delta variant. Covid-19 hospitalisation and death has mostly become a condition of the unvaccinated. However, Delta – or an even ‘tougher’ new variant could potentially change this. In itself, though, Delta’s high transmission rate is not necessarily a concern, because the natural tendency of any virus is to mutate into a milder (non-life-threatening) form over time.

Antibodies alone do not protect against the disease; vaccination is a must

A large share of the Indian population has antibodies against the disease, but that did not prove to be of much help during the second wave. Ultimately, what helps build resistance to the disease is vaccination. Therefore, governments across the world must prioritise getting unvaccinated people vaccinated, rather than – as some countries are now doing – shifting the focus to booster doses. India’s vaccination rate is much lower than in other nations, such as China or Canada, where over 70% of the population has already been vaccinated.

India possesses rich data that can help inform strategy, and save lives

Given its large population and slow vaccination drive, India will need to conduct intensive research on issues such as the efficacy of a single dose, or even mixed dosages, including against the newer variants. This can be done via large-scale randomised trials and will help determine the need for booster doses, or alternatively, regular (annual or half-yearly) vaccinations. India needs to also consider producing accurate, real-time case and mortality data that can identify the hotspots. Since all vaccinations are linked to Aadhaar numbers, it is quite feasible for India to produce robust data with little additional effort.

An opportunity to solve some of India’s other healthcare issues in one go

India, unlike most developed countries, lacks an adult vaccination programme. The current projections around Covid-19 suggest that going forward, people will need to be regularly vaccinated against the disease. This creates a unique opportunity for India to initiate a more inclusive vaccination programme covering all adults. Possible candidates for inclusion in such a programme would be annual vaccines against the flu, pneumococcal disease, tetanus and – especially for females – HPV. While a general immunisation programme need not centre around Covid-19, there is a chance here to prevent large-scale disease and death in one shot.

THINK TANK