Seven in ten of the deaths of working age adults involving coronavirus between March 9 and June 30 were likely to be the result of an infection acquired before lockdown, new figures show.

There were 5,330 deaths involving Covid-19 of 20 to 64-year-olds in England and Wales, the Office for National Statistics (ONS) said.

Of these, some 72 per cent, or 3,839 deaths, occurred on or before April 25 and are likely to be as a result of an infection acquired before lockdown.

The ONS’s assumption is based on evidence that the maximum time from infection to symptom onset is 14 days, and there are around 20 days on average from symptom onset to death.

Rates of death involving Covid-19 in men working in health and social care were around three times higher if the virus was thought to have been acquired before lockdown than if it was caught during the period.

For female health and social care professionals, deaths rates were around two times higher for those likely to have contracted the virus pre-lockdown.

Information on occupation was given for around three-quarters of the deaths recorded in the working age population.

The lockdown was linked to significantly lower rates of death involving coronavirus in all occupation groups, when compared with rates seen before lockdown.

In men, four of the nine major occupation groups – elementary; caring, leisure and personal services; process, plant and machine operatives; and skilled trades – had higher rates of death before and during lockdown compared with working age males.

Men working in caring, leisure and other service occupations had the highest rates of death involving Covid-19 during the lockdown.

They were two-and-a-half times more likely to die with Covid-19 than working age males during lockdown, with 81.3 deaths per 100,000 in these occupations, compared with 32.5 per 100,000 of working age males.

During this period, rates of death involving Covid-19 in male health and social care workers were significantly higher than those of males of the same age in the population.

Women had “far fewer” deaths, but those working in caring, leisure and other service occupations had higher rates of deaths involving coronavirus both pre- and post-lockdown, compared with women of the same age in the general population.

There were 31.3 deaths per 100,000 in these occupations, compared with 17.5 per 100,000 working age women.

This can largely be explained by the high rate of carers and home carers, who would be likely to have continued during the lockdown and not been able to work from home, therefore possibly increasing the risk of infection, it said.

The ONS said the reasons for its findings are complex but factors could include the level of exposure to others before and after lockdown, the ability (or not) to work from home, whether an occupation was furloughed and where someone lives.

It said: “During the pandemic, some occupations, such as health and social care professions, have continued to work in proximity to others; this is a factor that may explain the generally higher rates seen among such occupations.

“Other occupations, such as elementary and manual workers, are less likely to have homeworking opportunities, another possible factor.

“On the other hand, the lowest rates during lockdown may be because of certain occupations being able to work from home or because they have been furloughed.”