COVID-19 deaths: When does counting stop?

Singapore’s Ministry of Health (MOH) has confirmed 876 new cases of COVID-19 infection on May 10. Two casualties have been recorded on May 6, bringing the total COVID-19 deaths in the city-state to 20. Older age seems a common factor among them.

COVID-19 kills an estimated 13.4 percent of patients aged 80 and older, compared with 1.25 percent of those in their 50s and 0.3 percent of those in their 40s, according to a model-based analysis detailing elderly people’s heightened risk of death from SARS-CoV-2. [Lancet Infectious Diseases 2020;doi.org/10.1016/S1473-3099(20)30243-7]

The sharpest divide came at age 70, said the researchers. Although 4 percent of patients in their 60s died, 8.6 percent of those in their 70s did.

The individual-case data were collected for patients who died from COVID-19 in Hubei, China up to Feb 8, 2020, and from cases outside mainland China that were culled from government websites and media reports in 37 countries, including Hong Kong and Macau, until Feb 25, 2020. These data were used to estimate the time between onset of symptoms and death, or discharge from the hospital.

“The estimated overall infection fatality ratio for China was 0.66 percent, with an increasing profile with age,” said the researchers. “Similarly, estimates of the proportion of infected individuals likely to be hospitalized increased with age up to a maximum of 18.4 percent in those aged 80 years or older.”

Although China has succeeded in containing COVID-19 spread, such containment is unlikely in most countries, they added. “Much of the world will experience very large community epidemics of COVID-19 over the coming weeks and months. Our estimates of the underlying infection fatality ratio of this virus will inform assessments of health effects likely to be experienced in different countries, and thus decisions around appropriate mitigation policies to be adopted.”

The new estimates came as scientists scrambled to figure out the underlying reasons for older people’s greater susceptibility to the virus, and why some individuals mount a stronger immune response than others.

In Singapore, 98 percent of the new cases on May 10 were linked to known clusters. The other two percent are pending contact tracing. The MOH said it can now conduct over 8,000 tests daily, up from 2,900 in early April. This means more cases can be picked up in the coming days.

Investigation of 243 COVID-19 cases reported in Singapore from January 23–March 16 has identified seven clusters of cases in which presymptomatic transmission likely explained the occurrence of secondary cases. [MMWR Morb Mortal Wkly Rep 2020;69:411–415]

This has implications to public health practice, the researchers pointed out. “The possibility of presymptomatic transmission increases the challenges of containment measures … it underscores the importance of social distancing, including the avoidance of congregate settings, to reduce COVID-19 spread.”

Only with furious efforts like distancing protocols can the contagion be brought to heel. And only when the epidemic sputters to a halt can the deaths stop as well.