Around 30,000 NHS staff are self-isolating or off sick from work due to coronavirus as the UK faces the second wave.
NHS boss Sir Simon Stevens said the numbers underlined the need to control the spread of Covid-19 in order to protect the care that could be offered in the health service.
In July, Amnesty International revealed the UK has recorded one of the highest Covid-19 health worker death tolls in the world, at more than 540 fatalities.
Appearing at a Downing Street press conference on Thursday, Sir Simon was asked if coronavirus-related restrictions could last into the new year to help keep routine NHS services going.
Sir Simon said controlling community transmission was necessary to keep the NHS staffed.
“This will be a function of how well we are collectively able to get the infection rate down over the course of the coming month.
“But what we’re doing in the NHS anyway is we are going to make sure that we’ve got enough flexible facilities, that we’ve got as many nurses able to work as we can because where coronavirus takes off in the community that means that NHS staff themselves often are affected or have to self-isolate.
“Right now we’ve got around 30,000 NHS staff who are either off with coronavirus or having to self-isolate, that has an impact.
“So our success in controlling community transmission of coronavirus also is a force multiplier, to what the NHS itself can then provide in the way of care.”
Sir Simon’s comments come after he suggested on Wednesday that all patient-facing health service staff will soon be given routine Covid-19 tests.
He said new tests and increased capacity meant that testing for all frontline workers – regardless of whether they have symptoms – should begin within six to eight weeks.
Routine testing of NHS staff is already taking place in the hardest-hit areas.
Sir Simon said that, so far, 70,000 staff in those regions have been tested in recent weeks.
On Monday, Sarah-Jane Marsh, outgoing director of testing at NHS Test and Trace, suggested that routine staff testing would occur on a weekly basis.
Access to reliable testing as well shortages of personal protective equipment (PPE) were among the issues faced by health workers earlier in the coronavirus pandemic.
In September, NHS Providers, which represents NHS trust leaders, warned that a lack of testing was contributing to staff absences, putting services at risk.
There were widespread reports of PPE shortages during the first months of the pandemic putting staff and patients at risk.
The Department for Health and Social Care (DHSC) insisted it had never run out of PPE stock nationally but acknowledged that the crisis had put supply chains and distribution networks under “unprecedented strain”.