Viral tweet overstates UK’s lead in Covid-19 cases

A tweet with over 5,000 retweets claimed on 18 October: “There were 229,000 new cases of coronavirus in the world yesterday. The UK provided 20% of them. 1 in 5 of the new cases in the whole world was on our little island.”

That’s not quite the case.

Data from the University of Oxford’s Our World in Data project, which in turn relies on data from John Hopkins University shows there were 301,327 confirmed cases reported worldwide as of 17 October. The UK reported almost 15% of them, or just under 45,000. 

These figures are different to the ones used in the tweet. From subsequent tweets, the Twitter user seemed to be using Worldometer, which may collate its figures differently.The most recent figures from Worldometer suggest there were over 340,000 cases reported on 17 October, rather than 229,000 as specified in the tweet.

The Twitter user made their comment at 8pm Greenwich Mean Time, meaning it was still the morning in parts of the Western Hemisphere, for example, 10am in Hawaii. So it’s unlikely all of the day before’s statistics would be collated yet in this part of the world, especially following the weekend. 

Because 17 October 2021 was a Sunday, some countries such as Spain, Belgium and Honduras didn’t report figures at all, plus there may be delays in reporting numbers of cases. For example, the next day, on 18 October, the US reported over 116,000 new cases, compared to just 17,620 the day before. 

On 18 October, the day after the figures reported in the tweet, the UK reported around 11% of the world’s new cases.

This is why we often look at new Covid cases as a rolling seven day average, to avoid the artificial drop seen at weekends. If we look at the rolling seven day average of new Covid cases on 17 October, the UK had 10% of new cases, far fewer than the 20% claimed in the tweet. In comparison, the US had 21%.

The original tweeter clarified the time difference issue in a tweet several hours later, saying that it “alters the calculation somewhat”.

And it’s also worth bearing in mind that the number of confirmed cases reported on a given day does not necessarily represent the actual number of new cases on that date. According to Our World in Data, “this is because of the long reporting chain that exists between a new case and its inclusion in national or international statistics.” There have also been many concerns about underreporting of cases in some countries.

It’s certainly true that the UK has a lot of new cases compared to its population. But even when population size is taken into account, claims about the UK’s total cases can still be confusing.

In a tweet on 15 October, the New Stateman’s George Eaton claimed: “The UK has the *second-highest* Covid-19 case rate in the world, with only Romania recording more”. 

But this was only true for countries with more than 10 million inhabitants. He also tweeted a picture of the publication’s ‘Chart of the Day’, which did have a footnote with this caveat.

The accompanying article in the New Statesman did not mention this caveat in its copy, only in the footnote of the graph.

If you include all countries, the UK had the eighth highest number of new cases per million of its population as of 14 October 2021, at 570 cases per million. It was behind Latvia, Serbia, Georgia, Lithuania, Estonia, Romania (as the graph showed) and Mongolia.