Within a few months, the collaboration had published research papers that map out protein interactions and other features of the SARS-CoV-2 virus that have helped to identify drug candidates now being tested against it.

The pandemic could leave its mark on research collaborations for years to come.

And it might have intensified the challenges to international cooperation arising from long-standing political tensions, particularly between the United States and China.

Analysis by Nature suggests that the growth in research collaborations involving the two countries might have started to slow before the pandemic.

Another third were collaborating with someone who had worked in one capacity or another in the United States2

“As many as 90% of these international collaborations begin somehow face-to-face or side-by-side,” says Wagner, now a science-policy specialist at the Ohio State University in Columbus.

The story of rising international collaboration, aided over decades by cheaper travel and better digital connectivity, is now familiar.

In addition to the steady growth of international collaborations, one other trend has been clear for years: the papers that they produce tend to be cited more than domestically authored papers — a rough but useful measure of their relative impact on a field.

One study3 that examined subjective researcher assessments of biomedical papers suggested that, at least for a subset of the literature, international collaboration doesn’t correlate with better quality.

Although the majority of its papers are wholly domestically authored, its sheer publishing volume means that it has become the leading international partner for researchers in many other countries.

These now account for around 30% of international collaborations and 7% of all articles, according to a Nature analysis of Dimensions, a database owned by the analytics firm Digital Science in London.

Early in the COVID-19 pandemic, science leaders talked widely about leveraging global knowledge and working together.

According to multiple analyses of co-authorships of research studies4,5, including Nature’s own for this article, the first few months of the pandemic probably did see more international collaboration on COVID-19-related papers than was typical for non-COVID-19 research.

But collaboration was less common than for coronavirus research in previous years.

And in 2020 as a whole, international collaboration rates for COVID-19 research ended up being similar to those for all research, Nature’s analysis suggests (see ‘COVID collaborations’).

In a preprint4, Ying Ding, an information scientist at the University of Texas, Austin, and her collaborators tracked a decline in international collaboration relative to previous coronavirus research, but also noted a 3% increase in collaborations involving individuals who had never worked together before.

The pandemic, Ding says, might have given birth to some creative partnerships (see also ‘Finding that dream-team dynamic’).

Papers by lower-power teams do better when there is more of a hierarchy, she says; these teams need some people with more research experience.

The worst performers are those with high power and lots of hierarchy, Ding says.

If a team has ten authors — five from the United States, three from China, two from Singapore — they can identify leadership not just from the last author on the paper, but also from the concentration of team power.

Wagner and her colleagues looked at COVID-19 papers published up to the beginning of last October5.

They found that coronavirus research teams shrank over this period, and involved fewer nations than was the case before the pandemic.

Researchers have paid particular attention to collaboration between the United States and China, the two nations with the biggest scientific output.

In the first few months of the pandemic, these two countries collaborated on COVID-19 papers more than any other pair of nations, and at higher rates than they did for non-COVID-19 science, according to Nature’s analysis and work6 by Lee and John Haupt, an international-education specialist at the University of Arizona.

That was in part because so many of the early papers on the pandemic had authors from China.

But as the pandemic wore on, the United States turned instead to collaborating on COVID-19 papers with other countries, such as the United Kingdom, Nature’s analysis and Wagner’s work show5 (see ‘US COVID collaborations’).

Ding says she was affected by these restrictions first-hand when she was working with researchers in Chinese universities to study the flow of misinformation about the new coronavirus.

“Some of them said, ‘Sorry.’ They cannot work on COVID any more because that has to get approved,” Ding says.

The QBI was establishing connections in China before the pandemic, and things were going smoothly, says Krogan.

“The pandemic kind of triggered something, politically, I guess.” The QBI’s coronavirus research group currently has no official partners in China.

The data on collaboration during the pandemic are messy in part because of the massive publishing surge — the number of COVID-19 papers and preprints increased from about 5,000 in the first three months of the pandemic to 150,000 or more by the end of 2020.

In a few years’ time, Adams says, one might be able to look back and see ‘blips’ in the research record due to work that stopped because people switched to working on coronavirus, reduced their international travel, or shut down their laboratories.

Others see the pandemic as potentially amplifying some of the forces that work against international collaboration.

The drop in US–China collaborations on COVID-19 research that Wagner documented represents a small proportion of all the research the countries do together.

Nature’s analysis suggests that although the number of papers with both Chinese and US co-authors is still climbing, the fraction of China’s international collaborations that involve US authors has been declining since 2017 — even as the share of papers co-authored with some other nations, such as the United Kingdom and Australia, is rising.

Perhaps more importantly, visa restrictions imposed by the administration of former US president Donald Trump last year might have reduced the number of visiting scholars and students training in the United States.

And Chinese scientists already working in the United States might be less inclined to stay: some report feeling less welcome because of rising racial discrimination.

In 2020, the government said that Chinese researchers should be evaluated less on the volume of their work in international-journal databases such as the Science Citations Index, and more on the quality of their papers — and that assessments should also consider research in journals published in China.

The policy could have a profound effect on international collaboration, says Lee.

“It’ll undoubtedly have an effect when we’re not even able to nurture the early seeds in collaboration,” says Lee, who aims to explore the appetite for collaboration through interviews and surveys in the United States and China starting later this year.

This was mandated by the biomedical funding charity, Wellcome, for research that it funded on COVID-19, although there have been instances of people circumventing the rules by making data available ‘upon request’.

In theory, the push for open data might lessen international collaboration if it is no longer necessary to establish personal relationships to access data.

“It could actually, in some ways, enhance and increase international collaboration rather than diminish it,” she says.

Lang points out that during the pandemic, most major international clinical trials have been led by wealthy nations and involved treatments and vaccines that could be administered in hospital settings.

It could help to spur better, more independent research in low- and middle-income countries, but it’s not there yet, she says.

Lesley Thompson, vice-president of academic and government relations at the science publisher Elsevier, says that the company’s 2020 analysis9 of gender representation in science publications found that women typically have smaller networks of international collaborators than men do (see ‘Male and female collaboration networks’).

Several papers have documented how the pandemic probably exacerbated disparities that already existed between male and female researchersW

Leaders of the QBI coronavirus research group have considered these disparitiesJ

The pandemic exposed a lot of good things about how people work together, but also a lot of deficiencies, he saysJ

Houston, TX, United States

New York, NY, United States