A recent study suggested young adults ages 20-24 are primarily responsible for the transmission of the coronavirus. But the reality of how the virus spreads is more complicated.
As countries around the world face lockdowns, staggering death tolls, and overstretched healthcare systems, public attention has focused on countries that seem to have weathered the storm with relative stability and low mortality rates. Nations like South Korea, New Zealand, and Germany have been the subject of heightened interest from both professional researchers and armchair epidemiologists.
A new study about German compliance with soon-to-be-relaxed social distancing rules achieved massive buzz on social media, with headlines claiming that young people were much more likely to break the regulations and thus continue the spread of the novel coronavirus. The idea was particularly digestible after a weekend in which many photos emerged of young people crowding parks in big cities, and taking part in anti-lockdown protests:
Relative risk higher for young people
"Twenty- to 24-year-olds are driving the coronavirus pandemic in Germany," claimed the Tagesspiegel daily, with several other German news outlets picking up the story. But is that conclusion really borne out by the data?
The study was conducted by Harvard epidemiologists Edward Goldstein and Marc Lipsitch using data from Germany's center for disease control, the Robert Koch Institute (RKI) and published in Eurosurveillance, a journal on infectious diseases and epidemiology.
Using data on the number of confirmed coronavirus infections in the last week of March and the beginning of April, the scientists concluded that the relative risk (RR) for COVID-19 cases for residents of Germany aged between 15-34, and particularly between 20-24, was noticeably higher than all other age groups. They also determined that similar patterns had emerged in South Korea, where individuals 20-29 years old had the highest number of detected cases.
Read more: Coronavirus in Germany: 100 days later
However, the paper also notes that the scientists were thus far unable to determine the reason behind the increased risk. Though they do mention "the possibility of elevated mixing because of lesser adherence to physical distancing guidelines for persons aged 15–34 years," they neglect to touch on the fact that many young people are more likely to work in high-contact jobs, for example in service industries. Though many of these sectors were temporarily shuttered during the lockdown, the period of study includes a time when many young people could have contracted the disease at work before the new regulations came into place.
The study also does not note that young people are less likely to own cars, and therefore have a continued need for public transportation, or factors specific to Germany, such as the fact that the outbreak in the country originated with young people returning from skiing holidays in Austria and then coming together to celebrate Carnival — the festive season widely celebrated in western and southern Germany — thus spreading the virus in a more concentrated manner amongst their age cohort during large public gatherings.
Further complicating the matter is a separate study released on the same day as the one looking at the RR factor and different age groups. This one examined the small western city of Heinsberg, known as Germany's epicenter for COVID-19. To gather their data, scientists from the University of Bonn tested over 900 individuals from Heinsberg. Results indicate that some 20% of carriers in Germany could be asymptomatic. This means that some 1.8 million people could have thus far been infected with the coronavirus across the country, a number ten times higher than the official count given by the RKI.
Glut of dubious academic studies
There have also been calls from the scientific community for the public to cast a more discerning eye on the various coronavirus papers proliferating on the internet, many of them in pre-publication and therefore not yet peer reviewed. Amongst those that have been peer reviewed, experts say, there is still the problem that qualified reviewers are currently too few and too overworked. The new study in Eurosurveillance is listed as a rapid communication, a term used by academic journals to denote when a peer review process was hastened in order to publish an article related to an emergency or vital for the public interest. Similar complaints about a lack of proper peer review have also been levelled at the Heinsberg study.
Despite viral images of picnickers and protesters on social media, there is no scientific evidence that young people are more likely to disregard social distancing rules in Germany.