Factors such as a younger population, early lockdown and some level of general immunity may have helped India and other South Asian countries keep the Covid-19 mortality rate down compared to other nations, says a study.

Bengaluru-based epidemiologist Dr Giridhara R Babu and researchers from the Philippines and the US conducted the study, which was recently published in the journal Science Direct.

The South Asian region comprises eight countries — Afghanistan, Bangladesh, Bhutan, India, the Maldives, Nepal, Pakistan and Sri Lanka — and is home to one-fifth of the world’s population. It accounts for 21 per cent of the reported Covid-19 cases in the world and 11 per cent of the deaths. Despite low level of pandemic preparedness, the countries have done well in mounting an appropriate response, the study notes.

“The region has a lower rate and proportion of deaths attributed to Covid-19, despite case surges similar to the rest of the world,” it states.

Initial Covid-19 projections had placed South Asia at a higher risk of suffering more fatalities because of high population density, greater burden of comorbidities, socioeconomic vulnerabilities and poor healthcare infrastructure. A younger population with the average age of 25 may be a factor in the lowerthan-expected mortality rate, the researchers have observed. The relatively late onset of the pandemic in South Asia may have also played a part. “As the number of Covid-related deaths disproportionately affects the older population, these countries might have a unique advantage,” says the study.

Immunity is another aspect. “Possible exposure to other coronaviruses in the past may have helped the population in these countries to develop innate immunity, which could have reduced the severity of the infection. We have listed out hypotheses, but they need to be proved,” said Dr Babu, head of life-course epidemiology at the Public Health Foundation of India (PHFI). The researchers point out that data inaccuracies could have resulted in an underestimation of deaths in South Asia.

The researchers analysed countries’ preparedness using the Global Health Security Index Score. India scored 46.5 out of 100, Bhutan 40.3, Pakistan 35.5, Nepal 35.1, Bangladesh 35, Sri Lanka 33.9, the Maldives 33.8 and Afghanistan 32.3. “Each country had a different preparedness level. They have witnessed a lower mortality rate compared to the UK and the US, which had better preparedness,” Dr Babu told STOI.

The study’s other researchers are: Sonalini Khetrapal from Asian Development Bank, Philippines; Dr K M Venkata Narayan from the Emory University School of Medicine, US; and R Deepa and Daisy A John from PHFI.