Why can’t we compare countries’ coronavirus responses?

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Many countries have been praised for their swift responses to the coronavirus, while others have been criticized for doing too little, too late.

by Tala Ramadan -Source: Annahar

People wearing face masks attend a service at the Yoido Full Gospel Church in Seoul, South Korea, Sunday, May 10, 2020. (AP Photo)

BEIRUT: The race to track and slow the coronavirus has been very much a numbers’ game as many observe epidemiological numbers like infection rates and death counts which have been a grim presence in this pandemic, represented by circular tumors growing outward on maps.

Many countries have been praised for their swift responses to the coronavirus, while others have been criticized for doing too little, too late.

Research has questioned the usefulness of death rates in judging countries’ success in battling COVID-19 highlighting the geography and demographics play a significant role in how countries have been affected.

Before diving into the details from different countries, it’s worth looking at some of the broad reasons why death rates can look so starkly different from place to place.

Death rates are complicated

Confusion about what people mean by “death rate” can make countries’ numbers look vastly different, even if their populations are dying at the same rate.

There are two different kinds of fatality rates; the case fatality rate is the proportion of people who die who have tested positive for the disease. The infection fatality rate is the proportion of people who die after having the infection overall; as many of these will never be picked up, this figure has to be an estimate.

In other words, the case fatality rate describes how many people doctors can be sure are killed by the infection, versus how many people the virus kills overall, says Carl Heneghan, an epidemiologist and director of the Centre for Evidence-Based Medicine at the University of Oxford.

To see what a difference this makes, consider 100 people who have been infected with Covid-19. Ten of them have it so severely that they go into hospital, where they test positive for Covid-19. The other 90 are not tested at all. One of the hospital patients then dies from the virus. The other 99 people survive. That would give a case fatality rate of one in 10, or 10%. But the infection fatality rate would be just one in 100 or 1%.

Another measurement is how many deaths have occurred compared with the size of a country’s population; the number of deaths per million people, for example. But that is determined partly by what stage of the outbreak an individual country has reached. If a country’s first case was early in the global outbreak, then it has had longer for its death toll to grow.

When studying these comparisons, it is also worth remembering that the vast majority of people who get infected with coronavirus will recover.

Countries collect data differently

The number of tests does not refer to the same in each country, one difference is that some countries report the number of people tested, while others report the number of tests (which can be higher if the same person is tested more than once) while other countries report their testing data in a way that leaves it unclear what the test count refers to exactly.

There are big differences in approaches to testing too. The UK has prioritized testing frontline workers and people who are so ill they need to be hospitalized. Other countries, like South Korea, have adopted blanket testing models. This means one country’s data may be less complete than others, making its death rate per confirmed case look relatively high.

Population factors

Real differences in the populations in different countries exist, demographics are particularly important in terms of average age, or where people live. When it comes to the age structure, a comparison of death rates between countries in Europe and Africa wouldn’t necessarily work, because countries in Africa tend to have much younger populations.

Different health services

Health systems play a crucial role in trying to control a pandemic, but they are not all the same.

“Do people actively seek treatment, how easy is it to get to hospitals, do you have to pay to be treated well? All of these things vary from place to place,” says Prof Andy Tatem, of the University of Southampton.

The level of comorbidity, the number of other conditions, such as diabetes, heart disease or high blood pressure – which people may already have when they get infected, is also another main element to consider.

All these factors suggest that while many may be able to draw some conclusions about the success of nations’ COVID-19 responses, they should exercise caution when making direct comparisons.

 

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