COVID-19: Italy had 5.8 million cases by March 28, says study

Lockdowns reduced transmissibility in European nations but not template for all countries

By Banjot Kaur
Published: Tuesday 31 March 2020

Italy could possibly have a higher number of cases of those infected by the novel coronavirus (SARS-CoV-2), than the current reported tally of 0.1 million cases, according to a study by the Imperial College in London, United Kingdom (UK).

The same could be the case for 10 other European countries, according to mathematical projections in the study, released on March 31, 2020.

Approximately 5.8 million people were infected in Italy by March 28, affecting 9.8 per cent of the population there, according to the projections.

The percentage of the population of any given country affected by the virus is known as its attack rate.

The projections suggest around seven million in Spain were affected, with the virus’ attack rate there at 15 per cent.

Around 0.6 million of Germany’s population was affected, with an attack rate of 0.7 per cent, according to the projections.

Similarly, the attack rate of the virus in Austria, Belgium, Denmark, France, Norway, Sweden, Switzerland and the UK was at 1.1 per cent, 3.7 per cent, 1.1 per cent, 3 per cent, 0.41 per cent, 3.1 per cent and 3.2 per cent, respectively.

The researchers attribute the true number of cases not being reflected in current numbers to “mild and asymptomatic infections as well as limited testing capacity”.

Restrictions imposed in 11 European countries averted 59,000 deaths by March 31, according to the study.

The current number of reported deaths in the countries was 17,787 till March 28, while the number of projected deaths was 28,000 till March 31, according to the study.

The number of projected deaths without restrictions, however, could have reached 87,000, the study said.

Lockdowns had the most impact among all restrictive measures on reducing transmissions, followed by school closure, banning public events, social distancing and self-isolation, according to the study.

The maximum impact on decreasing the reproductive number — the number of people infected by one infected person — was affected by lockdowns, followed by all other measures.

The European countries that were assessed were also nowhere close to herd immunity, a concept floated by the UK to fight the infection, according to researchers.

Herd immunity is a stage in an epidemic where 50-75 per cent of the population in a territory develops immunity to a disease.

The virus is allowed to spread and infect more people, who in turn develop antibodies over time to fight the infection. A large number of people — known as the ‘herd’ — then become immune.

“With Rt (revised reproductive number as consequence of restrictive measures) values dropping substantially, the rate of acquisition of herd immunity will slow down rapidly. This implies that the virus will be able to spread rapidly should interventions be lifted,” the study said.

It warned that future projection of deaths depends on adherence to restrictive measures, also knowns as non-pharmaceutical measures in public health parlance.

The study’s authors, however, said what proves good for Europe may or may not be the template for countries across the world.

“It is too early to be sure whether similar reductions will be seen in countries at earlier stages of their epidemic,” the study said.

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