I'm not so sure this is the cause as in the countries I am familiar with (UK, Spain), such sentiment long preceded the pandemic.
It's a complicated issue and immigrants aren't some homogenous fungible group. Many European countries have had a very different type of immigration to what the US has had, for example.
Immigrants coming on visas to work (and having to pay all the related visa fees and other surcharges like the NHS surcharge in the UK) are generally much more accepted than the influx of asylum seekers who are dependent upon the State and have no reliable criminal background check etc.
Politics feels increasingly polarised though so I'm not sure we'll arrive at the nuanced solution it deserves.