At the time of writing there were 11,001 confirmed COVID-19 cases in India, (covidindia.org, April 14, 10 pm). The rate of doubling which increased to every 4 days is now back at about 5 days. The true success of the lockdown will only be clear in the coming weeks as it is possible that the confirmed cases and deaths being identified now were infected by the virus before the lockdown. However the extended lockdown is a good opportunity for states to expand testing and flatten the state level curves.
While we have seen cases spike up in the last week, it could be attributed to increase in testing in the last couple of weeks. 11,001 cases diagnosed after about 217,554 tests (from covidindia.org, April 14, 10 pm) indicates a positive case rate of around 5%. This number could imply either poor accuracy in identifying susceptible individuals for testing, or a low rate of community spread. In the US for example, the same rate is about 20%, in Italy about 16%, Germany around 10%, and South Korea at just around 2% (as accessed on April 14, 10 pm).
This number alone is not the best indicator of the spread as the low rate in South Korea could be attributed to early onset of and high rate of tests and not poor detection. In the US on the other hand, the high number seems to indicate late onset of massive testing and wider community spread. In both countries tests conducted per million population is very similar, 9156 in the US and 10,288 in South Korea.
Number of tests per million is a good indicator for scale of testing given a country’s population but it isn’t the best indicator when tests are done through contact tracing or network tracing. India will find it next to impossible to achieve 10000 cases per million in a few months as it would mean conducting about 13 million tests. US has conducted less than a fourth of that number so far, with more than 50 times as many cases as India (as on April 14).
A prevalence model
For state governments, it is critical to have a model of how many cases could be prevalent in their states and whether they require medical care or not. A model from the University of Göttingen suggested that only 9% of cases are being detected worldwide. It is not to suggest that all countries are performing poorly in testing. It could suggest that a majority – 85% of them, by one estimate – don’t feel any symptoms of the infection, or only mild ones, so they never go for a test even as they could be carriers.
For India, a recently submitted paper using the same model as the University of Göttingen and estimated that on April 8, 2020, when the number of detected cases were 5420 from about 1 lakh tests, there were about 150,000 lakh infected persons in the country. The same paper also estimates that Kerala is the most successful in detecting cases at about 40% success rate, while Rajasthan (7.8%), UP (4.8%), Karnataka (4.8%) and Haryana (4.1%) were moderately successful (only states with more than 100 cases were considered).
A silver lining
A more ominous statistic for state governments is the number of deaths. Of the 11,001 cases reported, 368 people died which is a mortality rate of 3.3%. The same number in the US is 4.1%, in Italy around 12.9%, in Spain around 10.4%, in Germany around 2.4%, and in S.Korea around 2.1%.
A higher death rate has been attributed to a higher share of elderly people in the populations of countries. A little under 23% of Italy’s population is 65 years or older making it the second oldest country only behind Japan, and Germany also has a considerably high senior citizens’ population of 21.4%. However, the death rate due to COVID-19 couldn’t be more different in both countries, at 12.9% and 2.4% respectively.
Similarly, older people in South Korea and the US make up 15% and 16% of the respective populations, but the 2.1% death rate in South Korea is almost half of the US’s 4.1%. Therefore, the proportion of the elderly, or for India a lack of it, does imply a higher vulnerability to COVID-19 but doesn’t necessarily correlate with the number of deaths.
The timely way out
Even in India, the aforementioned (preprint) paper argues that states like Kerala and Rajasthan, which had conducted a higher number of tests had reported fewer deaths and the recovery rate is high, even Kerala with the highest number of old age people had reported only 2 deaths till April 8.
Ever since the outbreak became a pandemic, it has been consistently reported that Germany and South Korea have the best testing mechanisms in the world, leading to early detection. Early detection is critical in providing timely medical care and preventing mortality, which seems to explain the low death rate in both countries.
On April 15, the Indian Council of Medical Research reported that the case load in India was rising exponentially, and rapid testing at scale was required. However, states should not be wary of a high number of cases still coming out as it could directly be related to greater testing rather than widespread infections. Since the recovery rate is high, the lockdown presents a good opportunity for states to trace, identify and quarantine as many people at risk as possible.
If the maximum number of people is detected within the lockdown period, pressure on the health system to quarantine and treat the sick will gradually ease.
However, every day about 49,000 people are born in India, and thousands of others need medical care every day. When the lockdown ends, people who may have delayed seeking medical care will rush to seek it. That might put additional pressure on states. The situation for the poor will be more desperate because, in the time of economic uncertainty and rush at public health centers, they might have no option but to spend out of pocket in private facilities. That may not be a good situation to address either for a policymaker of a politician.
This article originally appeared on Science The Wire on 19/04/21.