Contrary to the notion that COVID-19 has less death rate compared with influenza, WHO says about 3.4% of reported COVID-19 cases have died globally compared with generally far fewer than 1% of those infected with influenza.

Contrary to the general notion that coronavirus disease (COVID-19) has less death rate compared with influenza (commonly called as seasonal flu), globally, COVID-19 has caused more than three times the number of deaths in reported cases than influenza. Across the world, about 3.4% of reported COVID-19 cases have died compared with generally “far fewer than 1% of those infected” with influenza, WHO Director-General Tedros Adhanom Ghebreyesus said during a press briefing on March 3.

As on March 4 (10.15 am), the number of confirmed cases globally is 93,136 and deaths at 3,198. The total number of cases reported from mainland China is 80,151 and deaths at 2,943. With 4,812 cases (28 deaths), the case load in South Korea is the highest outside China. At 79, Italy has reported the most number of deaths outside China, and is closely followed by Iran with 77 deaths.

The reason why COVID-19 causes more deaths compared with influenza is because COVID-19 “causes more severe disease than seasonal influenza”, the WHO Chief said. Also, due to its recurrence every year, people have built some level of immunity against seasonal influenza, which is not the case with the novel SARS-CoV-2 virus and hence more people are susceptible to SARS-CoV-2 infection.

In the case of China, as on February 20, the case fatality ratio (ratio of deaths from a disease to the total number of diagnosed cases) was 3.8% — 2,114 deaths in 55,924 confirmed cases. The case fatality ratio was high for Wuhan (5.8%) and low for the rest of mainland China (0.7%).

In China, the mortality varied in people based on age and underlying conditions. The highest mortality of 21.9% was seen among people over 80 years of age, while among retired patients but less than 80 years the mortality was 8.9%. Patients who did not have any underlying conditions were less likely to die (1.4%) than people with comorbid conditions – cardiovascular disease (13.2%), diabetes (9.2%), hypertension (8.4%), chronic respiratory disease (8%) and cancer (7.6%).

The WHO Chief underlined that transmissibility of SARS-CoV-2 virus that causes COVID-19 is less compared with influenza though both SARS-CoV-2 and influenza spread through small fluid droplets when an infected person coughs or sneezes. While people infected with influenza but not yet sick are major drivers of transmission, that does not appear to be the case for COVID-19.

“Evidence from China is that only 1% of reported cases do not have symptoms, and most of those cases develop symptoms within two days,” the WHO Chief said.

Published in The Hindu on March 4, 2020