For the past five decades, the United States has been a top destination for international early-career researchers to do their training in a PhD or postdoctoral post. Since the 1960s, post-cold-war US diplomatic policies have aimed to attract foreign scholars, especially those in then-budding democracies.

After a steady increase, numbers peaked in 2016, when more than one million students – undergraduate and graduate – were enrolled to study in the United States. The number of international students then began to decline slowly: graduate-student numbers dipped by 1.3 per cent, to 377,943, in 2018, according to the Institute of International Education, a student-exchange non-profit organization based in New York City.

During the 2020-21 academic year, the first of the Covid-19 pandemic, the number sank by 12.1 per cent, to 329,272 graduate students. That same year, numbers of international scholars in the United States (specifically, postdocs and visiting researchers) plummeted by 31 per cent, from 123,508 to 85,528.

It’s unclear whether those numbers will recover, or how long that might take. In August, The Wall Street Journal reported that the number of international-student F-1 visas issued to Chinese students, who make up the overwhelming majority of people coming to attend US universities, had declined by more than 50 per cent in the first six months of 2022 compared with the same period in 2019.

Furthermore, a September 2021 poll for the US-China Perception Monitor found that 62 per cent of Chinese respondents had a view of the United States that was either “very unfavourable” or “unfavourable”.

Universities in countries such as Australia and Canada, which are increasingly reliant on foreign-student tuition fees, also saw Covid-19-related declines in the number of international students in 2020. Australia has struggled to re-establish an international-student pipeline following its stringent Covid-19 border closure.

Although the number of study-permit holders in Canada increased to more than 750,000 international students for the 2022-23 academic year, applicants from Africa have complained of excessive visa-application delays. Last month, Immigration, Refugees and Citizenship Canada stated that more needs to be done to stamp out internal racism against African applicants.

The reasons for international-student career decisions are undoubtedly complex. In the case of the United States, some would-be students have lingering concerns about Covid-19. The high cost of living is a key issue for non-citizens, with the median rent for the 50 largest metropolitan areas hitting a record high of $1,879 per month in July. Many universities require international students to have health insurance, which can be expensive: for example, a medical insurance plan for graduate students at the University of California, Berkeley, costs $3,186 per semester for the 2022-23 academic year.

But not every institution offers insurance subsidies. Other factors include rising tensions stemming from US politics becoming increasingly divisive, a process that accelerated during Donald Trump’s presidency. The US FBI’s criminal-data repository documented 11,126 victims of hate crimes in 2020 – the highest number since 2008 – with 82 per cent of those crimes motivated by race or sexual orientation. According to the non-profit organisation Stop AAPI Hate, more than 11,400 hate incidents against members of Asian communities have been recorded since 2020.

Nature spoke to five researchers who shared their thoughts on why they’ve chosen not to pursue positions in the United States. The reasons ranged from legislative decisions that block a woman’s right to an abortion in many states, the frequency of mass-shooting events (586 so far in 2022), the high cost of insurance-based healthcare, persistent racism and the rise in hate-crime violence, spurred by Covid-19’s emergence in Asia and divisive culture wars.

The United States has always been off the table for me. My biggest qualms are the cost and availability of healthcare, the gun violence and the rise of white supremacism. My impression is that people on the right of the political spectrum have adopted the stance that Covid-19 was ‘caused by China’, which, in turn, gives them the ‘right’ to punish anyone whom they associate with the country.

My main concern is how white supremacists can actively provoke or harass people, with few or no repercussions. As someone who isn’t white, being in one of the right-wing US states would not appeal to me.

I grew up in east Malaysia and then did my bachelor’s and master’s degrees at the University of Glasgow, UK, before moving to Denmark to get my PhD in microbiology at the University of Copenhagen. I’m now in the middle of a two-year postdoctoral contract in the United Kingdom.

As a Malaysian, immigration status is another concern. As far as I’m aware, beyond winning one of the few immigrant visas distributed through a lottery system, there’s no easy way, as a student or postdoc, to become a US resident. If any friends or family want to visit, they would have to go through a lengthy US visa-application process. [Editor’s note: The Diversity Immigrant Visa Program provides up to 50,000 immigrant visas annually.] In most European countries, you apply for residency, then stay on once it’s approved.

There are other aspects of daily life to consider. Right now, I am in a relationship with a British citizen who lives in Ipswich, only a 40-minute train ride away. The main thing anyone should consider when moving to a new country is how much money one needs to survive there. In England, for example, I can take public transport or bicycle anywhere I need to go. In many US cities, I would need a car, which adds considerable expense.

After I completed my master’s at York University in Toronto in my home country of Canada, there weren’t a lot of PhD options here in my narrow field, so I had to choose where to move abroad. I was already feeling uncomfortable about the United States because of the lax gun laws, but I also have health conditions that I need to consider. I knew that universities offer insurance, but I worried that it might not adequately cover my needs.

In late 2017, there was a period of time when a US Republican party plan to update taxes included a provision to heavily tax graduate-student tuition waivers. That piece of the plan eventually got dropped, but I realised that things can change very quickly in the United States. I was not going to risk going to a country where I could be destitute – either through healthcare costs or because of a rapidly shifting tax environment.

Now I’m in Europe doing my PhD in Austria, and I get paid around €30,000 ($29,800) a year, including five weeks’ paid holiday. I also receive a retirement pension plan, and the healthcare, which is largely publicly funded, is wonderful. I have no complaints. Now I have a year left, and am looking for postdoctoral positions. It hasn’t even crossed my mind to apply for US funding. One of the chief reasons is that it’s not a great place for people like me who identify as queer.

From the transphobic laws to protests against drag queens to the horrific shooting that left 49 people dead at the gay nightclub Pulse in Orlando, Florida, in 2016, the United States seems to be a place where it’s dangerous to present as anything other than cisgender and straight.

• A Nature report