The number of virus patients in Northampton General Hospital and Kettering General Hospital has risen nearly ten-fold in two months.
Reintroducing mask-wearing in all areas of the two hospitals aims to reduce infection risk to vulnerable patients and help prevent staff absences.
In a joint statement, KGH and NGH chief operating officers, Faye Gordon and Palmer Winstanley, said: “The UK is now experiencing a very significant spike in Covid-19 cases and the current variants are very infectious.
“As a result we are asking all patients and visitors attending our departments to please wear a mask.
“Clearly hospitals have many hundreds of patients who already severely ill, and in significantly at-risk groups, and we must do our utmost to protect them from Covid-19.
“We understand that wearing masks, particularly in the current warm weather, is challenging. But it is very important to prevent the spread of Covid-19.”
Numbers of Covid-19 patients occupying beds in the two hospitals dropped as low as 15 beds in May.
But latest figures show 136 patients needing treatment for the virus — 68 each at NGH and KGH — while the number staff being forced off work after testing positive or having to isolate is the highest since since February.
Latest Government weekly figures showed showed 2,165 positive Covid tests reported in Northamptonshire during the last seven days to Wednesday (July 6) compared to 510 at the beginning of June.
Latest NHS England figures, now published weekly instead of daily, also revealed nine Covid patients are sadly known to have died at NGH and KGH in 10 days up to Wednesday (July 6).
Some exemptions to mask wearing still apply, as they have throughout the pandemic, including young children, people with learning difficulties or mental health issues, and those with certain health conditions such as severe asthma.
NHS chiefs fear the current rise in cases — fuelled by new Omicron strains known as BA.5 and BA.4 — is just a prelude to what could happen later in the year.
Dr. Layla McCay, policy director at the NHS Confederation, warned: “The third major Covid wave of the year and with a couple of new sub-variants thrown into the mix, provides a preview for winter that is concerning NHS leaders. As well it might.
“Despite generally reassuring messages from the Government, it will not have escaped their attention that hospital admissions of patients with Covid-19 have been rising sharply.
“Clearly this is not yet near January levels. It’s no cause for panic but neither is it a trend to be brushed off.”
Dr McCay revealed that some NHS hospitals have already brought back Covid-only wards and are reporting increases in virus-related staff sickness.
But she added: “Analysts are predicting a more significant Covid-19 wave cresting on our shores around October.
"It will probably coincide with flu season. It is almost inevitable that a noxious combination of Covid-19 and bad flu will make many people ill and significantly disrupt healthcare services.”