Even before Donald Trump announced that he intends to temporarily suspend immigration to the United States because of Covid-19, it was becoming clear that the effect of the virus on migration would be powerful, long-lasting and unfortunate.

Many countries besides the US have already shuttered or severely limited entry from foreigners — and many of those restrictions will not be so easily removed when the worst of the pandemic has passed.

First, there is no guarantee that a good vaccine will be ready quickly, even within two years. There is still no vaccine, for instance, for the common cold or HIV-Aids.

Even if the US has Covid-19 under control, there might be persistent if small pockets of Covid-19 in other countries, including populous, poor countries such as India, Pakistan and Nigeria. The US may be reluctant to take new migrants from those parts of the world.

Whether or not that reaction is rational, it is easy to imagine the public being fearful about the potential of immigration to contribute to a pandemic resurgence. It does seem that regions able to restrict immigration relatively easily — such as New Zealand, Iceland and Hawaii — have had less severe Covid-19 problems.

New York City, which takes in people from around the world, has had America’s most severe outbreak. And the recent appearance of a second wave of Covid-19 in Singapore has been connected to ongoing migration there.

I have never thought the Federal Government would build Trump’s wall on the US-Mexico border. But now I wonder whether it may well happen — perhaps in electronic form.

There is another side to this issue, of course: many countries may decide to continue to limit visitors from the US. The American government may then respond by restricting immigration from those countries. This kind of tit-for-tat retaliation is not always rational, but it is a pretty common phenomenon in international relations.

Alternatively, maybe many poorer (and richer?) countries will acquire “herd immunity” even without good access to a vaccine. But that will be hard to prove, and the casualties that mount along the way may scare the US public away from allowing more immigration from those countries, even if their citizens end up as safer bets than Americans.

In recent times, China had been the largest source of immigrants to the US These days, it is difficult to imagine a member of the US Congress taking to the floor and demanding that America open its shores to the Chinese once again, no matter what the actual level of safety.

In addition to these effects, many migrants living in the US might go back home. Say you are from southern India and live in Atlanta, and typically your parents or grandparents come to visit once a year. That is now much harder for them to do, and will be for the foreseeable future.

India also might make it more difficult for Indian-Americans to return to visit their relatives, perhaps demanding an immunity certificate for entry. Many of these migrants will end up returning home to live in their native countries.

Even if a vaccine comes along in a few years, restrictions on immigrants will have become the legal status quo — and in a democracy with a lot of checks and balances, status-quo bias can be very strong. Those restrictions are not likely to be reversed very quickly.

In spite of all those possible restrictions, the pandemic itself may offer new reasons to embrace some forms of migration, if only to help Western economies continue to function.

Many jobs are now more dangerous than before because they involve face-to-face contact and time spent in enclosed spaces. Such professions as nursing and dental assistants, for example, already attracted many immigrants even before Covid-19. Working on farms may yet become more perilous if the virus strikes farmworker communities.

New migrants from poorer countries will be willing to take on these risks — for extra income of course — but most US citizens will not go near them.

The reality may be an uptick in some forms of migration, mostly for relatively hazardous jobs. There could be a national guest-worker programme, managed by quota by profession, to ensure that such jobs are filled. It is a little-known fact that last month the US Government eased H-2 visa rules, in part to make it easier for Mexican farmworkers to enter the US country and work to secure the food supply chain. And this was from an administration not favourable to greater immigration.

So, yes, immigration is likely to remain at depressed levels for years to come. At the same time, businesses will probably continue to furtively appeal for foreign workers for dangerous sectors, hire them and then keep many of them at arm’s length from mainstream American society.

That, at least as much as any reduction in overall levels, could be what the next wave of immigration looks like.

• Tyler Cowen is a Bloomberg Opinion columnist. He is a professor of economics at George Mason University and writes for the blog Marginal Revolution. His books include Big Business: A Love Letter to an American Anti-Hero