UK Prime Minister Boris Johnson announced improved sick pay during the coronavirus crisis, meant to ensure that those in self-isolation can claim pay from day one.

But in the US, according to official data from March 2019, nearly a quarter of workers have no access to sick pay.

Those workers have an incentive to ignore official advice and carry on going to work when they are sick — increasing the possibility for the disease to spread.

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The UK government announced emergency legislation on Wednesday that will guarantee instant sick pay for anyone self-isolating from the coronavirus.

The move is designed to ensure infected workers are not discouraged from quarantining themselves to control the spread of the virus in the UK, where there are so far 53 confirmed cases of the virus.

But across the Atlantic, the picture is very different. The US is one of only three rich countries in the world with no guaranteed sick pay for workers, according to the World Policy Center.

With no federal legal requirements for paid sick leave, the US has a patchwork of differing legislation at state and city level.

Data from the Bureau of Labor Statistics from March 2019 suggests that 24% of workers have no paid sick leave at all.

Morning commuters board a train in a crowded subway station in New York on May 11, 2016. Jewel Samad/AFP via Getty Images

As a result of situations like these, when workers suspect they have the coronavirus, nearly a quarter of them have a clear incentive not to self-isolate by continuing going to work — which flies in the face of health advice from the Centers for Disease Control and Prevention (CDC) aimed at stemming the spread of the virus.

The CDC recommends that anyone who suspects they are sick with the coronavirus should self-isolate at home — a difficult choice if that means forgoing your income.

The situation largely on where workers are in the US. For example, someone in Washington is entitled to one hour of paid sick leave for every 40 hours worked, according to the Washington State Department of Labor and Industries.

A worker in scrubs leaves the Life Care Center of Kirkland, a long-term care facility linked to several confirmed coronavirus cases, in Kirkland, Washington, U.S. March 3, 2020 Lindsey Wasson / Reuters

No such protections exist in, for example, Wisconsin, although a proposed insurance scheme is being considered, reported the Wisconsin Examiner. According to the Pew Research Center, cities were pre-emptively barred in 2011 from passing their own laws that would offer sick pay to workers.

The lack of legislation leaves the decision on whether or not to offer sick pay down to private companies. Between private policies, city laws, and state laws, 76% of US workers have some kind of sick pay — and 24% do not.

The Family and Medical Leave Act ensures that workers nationwide — at least, those who have been with a company of over 50 employees for more than 12 months — can't be fired for staying off work sick. But it doesn't guarantee pay.

As PhD management candidate and former policy adviser Karen Scott put it in an opinion piece for The Conversation: "These conditions create a near-guarantee that workers will defy public health warnings and trudge into their workplaces, regardless of symptoms."

"In this way, a manageable health crisis can spiral out of control," she added.

UK Prime Minister Boris Johnson. Getty

The UK is currently facing what Prime Minister Boris Johnson termed the "highly likely" prospect of the coronavirus crisis deepening in upcoming weeks.

In a briefing on Tuesday, Johnson announced emergency legislation that included potentially asking UK workers to work from home for at least three months, as Business Insider reported.

Official health advice also asks people undergoing testing for the virus to stay at home.

—UK Prime Minister (@10DowningStreet) March 4, 2020

But under current UK rules, a worker with coronavirus would only qualify for sick pay on the fourth day at home — something that today's announcement aims to change.

The government's new emergency legislation would bring that forward to the first day of coronavirus self-quarantine.

"I think that's the right way forward," said Johnson to parliament. "Nobody should be penalised for doing the right thing."