COVID 19 TESTING: INDIA VERSUS THE REST- WHERE DO WE STAND?
Covid 19, a global pandemic, which began in China in late December 2019, has spread to more than 200 countries in the world. The total numbers of Covid 19 infected people have been rapidly increasing in some countries such as USA, UK, Italy, Spain, Iran, etc. Compared to that, the rise in the number of cases has not been that rapid in India.
Are the numbers in India really low?
There is no doubt that the number of confirmed cases of Covid 19 in India is lower than many countries, considering that it has more than 1.3 billion people. As on 9th April, 2020, India has about 6500 confirmed cases of Covid 19, which is a miniscule number as compared to USA (4,54,000), Spain (1,52,400), Italy (1,43,600), Germany (1,15,100), France (1,12,900), China (81,900), Iran (66,200), UK (60,700), Turkey (42,300) and Belgium (25,000), the top 10 most affected countries.
What are the possible reasons for low numbers in India?
Several reasons have been put forward, however there is no confirmed reason for the low numbers of Covid 19 in India so far. Some of the possible reasons could be:
- Lesser number of testing for Covid 19 in India,
- Greater immunity against Covid 19 in Indians,
- Universal BCG vaccination in India,
- Lower virulence of SARS CoV 2 virus in India,
- Higher temperature and greater humidity in India.
We will leave points 2 to 5 for a later date, and the focus would be on point no 1 today.
How is India doing when it comes to Covid 19 testing?
In India, testing is done for high-risk groups, as suggested by Indian Council of Medical Research (ICMR). The latest guidelines published on 9th April 2020 have been enclosed.
11 million tests have been conducted across the globe so far. Most people look at tests conducted per capita and say India has done the least (0.04 per 10,000 population), so, has the least number of cases. However, there is no correlation between per capita tests and “flattening of curve”. Spain and Italy have done the highest number of tests per capita (18 and 16 per 10,000 population), however, they are still seeing huge number of cases. On the other hand, South Korea and Russia both have done fewer tests per capita (about 0.6 per 10,000 population), but they have flattened their curves.
A more useful indicator would be the positivity rate (number of confirmed cases out of the total tested), as this would give a true picture of disease prevalence.
The positivity rate is highest for Iran at 30% (30 samples out of 100 tested were positive). This rate was 28% for Belgium, 26% for France, 20% for US, 18% for UK and 17% for Italy. For India, it is 3.8% (about 4 people testing positive for every 100 tested). Germany that conducted a larger number of tests also has relatively lower positivity rate at 5.6%.
What does a lower positivity rate indicate?
Lower positivity rate means the infection is less prevalent. If we test more, the absolute number of cases would go up, however, the positivity rate is likely to reduce. This is because with more widespread testing, we would be testing more people without covid 19, including those with non-covid 19 respiratory infections. This trend in decline in positivity rates has been noted with an increase in the testing numbers in India over the past few days.
Should we test more?
- The main reason for limiting the number of tests is the cost factor and limited availability of testing kits.
- Other reason for not doing widespread testing is that testing would require people to come out of their houses, which could lead to greater spread of infection.
- Moreover, in the absence of a specific treatment for Covid 19, a positive or negative test does not make any difference in terms of treatment. People with mild symptoms should stay at home even if they test positive.
- If a person tests negative today, it does not add any value to the patient. He still needs to follow all the precautions to avoid getting infected with SARS CoV2 (similar to a person not tested). This is because a person who tested negative has an equal chance of getting infected in future, if he comes in contact with a Covid 19 positive patient.
ICMR strategy of risk-based testing seems appropriate for now. However, in future, it can be scaled up on need basis.