The frontline role of local convenience stores during the coronavirus pandemic and the heightened risk to their workers have come into the spotlight as tributes were paid to a popular staff member at a south London corner shop.

Q&A Why are men more likely to die from coronavirus? Show Hide UK data from the Office for National Statistics has revealed that men are almost twice as likely to die from the disease as women. The trend was first seen in China, where one analysis found a fatality rate of 2.8% in men compared with 1.7% in women. Since then, the pattern has been mirrored in France, Germany, Iran, South Korea and Italy, where men have accounted for 71% of deaths. So why are men more vulnerable? “The honest answer is none of us know what’s causing the difference,” said Prof Sarah Hawkes, director of the UCL Centre for Gender and Global Health. Early on, smoking was suggested as a likely explanation. In China, nearly 50% of men but only about 2% of women smoke, and so underlying differences in lung health were assumed to contribute to the difference. Smoking might also act as an avenue for getting infected in the first place: smokers touch their lips more and may share contaminated cigarettes. Behavioural factors that differ across genders may also have a role. Some studies have shown that men are less likely to wash their hands, less likely to use soap, less likely to seek medical care and more likely to ignore public health advice. These are sweeping generalisations, but across a population could place men at greater risk. However, there is a growing belief among experts that more fundamental biological factors are also at play. While there are higher proportions of male smokers in many countries, the differences are nowhere near as extreme as in China. But men continue to be overrepresented in Covid-19 statistics. Hannah Devlin Science correspondent

The man, identified for now only as Kumar, had worked at the Freshgo store in Gipsy Hill for more than 10 years. He died in hospital last week after displaying Covid-19 symptoms. Another worker from the same shop was also reported to be in hospital.

As tributes were paid to Kumar on a crowdfunding page set up to help support his family and on a community Facebook group describing him as a “tireless worker”, concerns were expressed about the exposure of those employed in the stores, where narrow aisles and single points of entry make physical distancing more difficult.

“Kumar was always so kind and friendly and gave a big smile when I’d go in with my son,” Alicia Aleksandrowicz said on the Facebook page. “I had been worried about the staff there for a while given the size of the shop, and this seems truly unthinkable.”

Making a donation on the crowdfunding site, Andrew Gurney said: “Kumar was an unsung hero … long hours, day and night, even before these troubling times. Then to stay open and working in such a close environment for the sake of the community was the ultimate sacrifice.”

His death is the latest in a sector providing employment to a significant number of middle-aged men, a group regarded as being at a higher risk than some others, and which also has a large component of people from BAME backgrounds, a demographic that is already bearing a disproportionate brunt of the impact of Covid-19.

It comes days after another death, that of Raj Aggarwal, whose last Facebook post showed him dropping off a carload of tea, coffee and biscuits to hospital workers, and who was a board member of the the Association of Convenience Stores.

The ACS’s chief executive, James Lowman, wrote on his blog: “This is a terrible loss that will be felt personally by many people in our industry, and it should also remind us: there are people putting themselves in harm’s way to help the country through these difficult times, and to lose one of them in Raj is a hard thing to comprehend and accept.”

He told the Guardian that challenges facing the sector included issues around sourcing and using personal protective equipment (PPE). While public health experts are currently not recommending the use of face coverings, shop owners have been improvising masks of different types, as well as dipping into their own funds to erect screens.

Some shops have received government support, but others, such as those on petrol station forecourts, have seen sales collapse – although in the main there had been an big increase in sales, he said.

“We’re seeing a sustained growth in sales, though the pandemic has changed how people have been using our shops,” said Lowman. “Individuals are tending to make fewer visits, but are loading bigger baskets. While the average spend in ‘peacetime’, if you want to call it that, might be on average £6.50, that has now doubled. People are also buying different things, so less confectionery perhaps and more household supplies.”

Despite this, he added, extraordinary costs were mounting, including for PPE and the cost of employing an extra person in some cases to act as a marshal at the doors.