Coronavirus Infection Rate: The Lancet
- 02 Apr 2020
- 3 min read
Why in News
A study in the Lancet Infectious Diseases has estimated the mean duration from onset of symptoms (coronavirus) to death to be about 18 days and that of hospital discharge to be about 25 days.
- This finding is based on data on 24 deaths that occurred in mainland China and 165 recoveries outside of China.
- Infection Fatality Rate
- Overall infection fatality rate for China, where coronavirus first hit, was 0.66%.
- Infection fatality ratio takes into account the total number of people that might carry the virus without showing symptoms. These people are not a part of the “official number of cases” in China.
- However, recently, China has disclosed the number of asymptomatic (people showing no symptoms) cases. China has found more than 43,000 cases of asymptomatic infection through contact tracing.
- Contact tracing is the process of identifying, assessing and managing people who have been exposed to a disease to prevent transmission.
- China has decided to devote greater screening to asymptomatic sufferers and those in contact with them.
- Infection Fatality Rate is lower than Crude Fatality Ratio
- Researchers from Imperial College, London, had earlier said that the ‘crude fatality ratio’ was about 3.67%, which is on a par with the World Health Organization (WHO) estimates.
- The crude rate does not take into account the severity of the infection, which means it just compares the total number of cases with the total number of deaths.
- Age and Severity of Coronavirus
- Severity of coronavirus depends on the age of a patient, and the overall case fatality ratio (number of deaths per positive case) could be 1.38%.
- In those above 60 years, it was found to be 6.4%; in those above 80 years, 13.4%; and in people aged below 60 years, 0.32%.
- The findings are based on all the laboratory confirmed and clinically diagnosed cases from mainland China (70,117).
- Implication of Study
- The estimates of the case fatality ratio for COVID-19, are substantially higher than for recent influenza pandemics (eg, H1N1 influenza in 2009).
- With the rapid geographical spread observed to date, COVID-19 therefore represents a major global health threat in the coming weeks and months.
- Till April 1, 8.53 lakh cases of COVID-19 had been reported world-wide, with 41,887 deaths.
- The estimate of the proportion of infected individuals requiring hospitalisation, when combined with likely infection attack rates (around 50-80%), show that even the most advanced health-care systems are likely to be overwhelmed.
- Estimates are therefore crucial to enable countries around the world to best prepare as the global pandemic continues to unfold.