As Covid-19 cases have climbed, public health experts have urged people to dump their cloth masks in favor of higher-quality options and to test more frequently to curb the virus.

The Centers for Disease Control and Prevention on Friday updated its mask guidance to note that the disposable N95 or KN95 masks offer the "highest level of protection" against the virus.

For some, the added financial burden is an irritation — but still affordable. To others, the prospect of paying $1 for a single disposable mask or $24 for a test kit is an economic impossibility, raising the specter that the pandemic will continue to exacerbate inequalities.

On Dec. 29, The Gateway Pundit, a far-right website that often spreads conspiracy theories, published an article falsely implying that the Centers for Disease Control and Prevention had withdrawn authorization of all P.C.R. tests for detecting Covid-19. The article collected 22,000 likes, comments and shares on Facebook and Twitter.

Pop-up testing sites have cropped up on street corners, in parking lots and on shopping properties across the country, but health and legal experts say many of these are unregulated and could be rife for nefarious activities like identity theft.

In the last few weeks, legislators and attorneys general in several states including Illinois, Maryland, California, Texas and Pennsylvania have said they will be investigating and introducing regulatory legislation overseeing these operations.

Numerous illegal, unapproved and unsanitary sites have been cautioned by state officials nationwide.