More than 800 people have attended the country’s emergency departments with covid and flu this week, with the HSE warning that the situation is only likely to get worse.
The health authority admitted the hike in cases is going to put huge pressure on hospitals and residential facilities and particularly impact the most vulnerable people.
It also said there may be a return to wearing masks in some healthcare settings, particularly as the dominant strain of covid currently circulating is highly transmissible.
The HSE said the number of people who came to hospital with flu rose from an already high 312 last week to 538 this week. The corresponding rise in Covid cases was from 144 to 282.
There are currently 30 outbreaks of covid in hospitals and 24 in nursing homes, again an increase from last week.
“Rates of covid and flu are rising now and over the next few weeks, which will put significant pressure on hospitals and residential care facilities in the short term,” said the HSE’s chief clinical officer Dr Colm Henry.
"We know from experience that a delayed peak in flu season, such as we are seeing now, will inevitably lead to further pressures throughout the healthcare system with heightened risk of outbreaks in all facilities and delays to discharging patients to nursing homes or step-down facilities if they have flu or covid."
He said anyone with respiratory symptoms should not visit hospitals and nursing homes.
“Every healthcare setting is assessing the risks locally and monitoring their own local risks, and this may lead them to take additional measures in certain settings, such as the wearing of masks if deemed necessary," he said.
Dr Éamonn O’Moore, the HSE’s director of National Health Protection, said: “We are now seeing a sustained rise in the levels of infection with both covid-19 and seasonal flu, including among people attending emergency departments and being admitted to hospitals.
He said health authorities are still collating data in Ireland and internationally on whether it will result in more illness requiring hospital care “but at this time we are not seeing that signal”.
“However, with more infection around, there is greater risk some people who are vulnerable could become ill and require hospital care and we still need to protect our vulnerable members of society, children and adults, by doing what we can to reduce the spread of respiratory viruses.”
The HSE urged people to go to their local pharmacy before going to their GP or emergency department if they have respiratory symptoms.
"It is still not too late to get vaccinated: People who have not done so should get vaccinated at their GP or pharmacy," a spokesperson said.
"If you are unwell you should stay home until 48 hours after your major symptoms have resolved; avoid visiting people who are more vulnerable if you are unwell, especially avoid visiting hospitals or nursing homes if unwell. And we remind people about good infection control practice, including washing hands regularly and covering nose and mouth if you have coughs and sneezes."