Hospitals, healthcare centres and nursing homes are battling to keep the so-called winter vomiting bug under control with new cases still being reported in some places.
With no specific treatment for the virus, members of the public are still being advised not to visit numerous acute hospitals and, in some cases, urged not to attend accident and emergency departments. Visiting restrictions have remained in place for months in some instances with visitors prohibited in many wards.
The virus is a "self-limiting" bug which cannot be treated and must wear itself out, while healthy people can overcome the symptoms within 48 hours. It has so far affected almost 2,000 patients throughout the Republic.
The latest figures from the National Virus Reference Laboratory (NVRL) in Dublin show most counties have been infected with the disease, with urban areas of Cork, Limerick and Dublin hardest hit. Counties with little or no infection include Sligo, Leitrim, Roscommon, Longford, Westmeath and Louth.
Suspect specimens from 6,623 patients were investigated for evidence of infection of the virus, known as Small Rounded Structured Virus (SRSV). A total of 1,845 specimens tested positive.
Dr Jeff Connell of UCD's Virus Reference Laboratory has underlined that the winter vomiting bug is highly contagious. "Someone who is affected expels millions of particles which spread by vomiting and excretion."
A hospital situation, with people vomiting, provides an ideal situation for the virus particles to spread. It also spreads from faeces. "People will not catch the virus from a toilet itself, but it is important to wash your hands and to be careful while changing children's nappies," he said.
"Any area where a lot of people are in close proximity to one another, like a hospital, a crèche, a bus or a plane will allow the spread of the virus," he added. "More people are enclosed around winter time and so the virus breeds more effectively." He said older people are hit harder by the bug, which causes severe dehydration.
The closing of wards alone will not rid hospitals of the virus, he noted. "It is very hard to decontaminate a ward. The closing of hospital wards to additional patients would only be an additional control measure. Good hygiene is the best way to contain the virus."
The number of people affected in Waterford Regional Hospital has increased, with an additional five staff (bringing the total to 177) and two patients (bringing the total to 81) suspected as having contracted the virus.
While visiting restrictions are being lifted in most of the hospital, two wards - one medical and one orthopaedic - remain strictly closed to visitors.
The South Eastern Health Board has appealed to members of the public to remain outside these wards and asked anyone who has had contact with the winter vomiting virus to stay away from the hospital.
At St Canice's Hospital, Kilkenny, there are two new suspected cases. Seven psychiatric patients are currently in isolation. It remains closed to visitors.
The Midland Area Health Board Area has recorded no outbreaks in any of its acute hospitals but reported an outbreak last week in Lough Sheever, a centre for people with disabilities in Mullingar, where approximately 20 people, including five members of staff, were infected.
The Mid-Western Health Board has recorded no new outbreaks since the end of October but visiting restrictions are still in place. Eleven hospitals and daycare centres under the MWHB have been affected with almost 200 patients and 151 staff infected. Its three major hospitals, Limerick Regional, Ennis General and Nenagh Hospital, recorded the most cases.
Louth County Hospital in Dundalk remains the only hospital in the North Eastern Health Board area with current cases.
There have been no new confirmed cases in the Western Health Board area in recent weeks, where hospitals are operating as normal.
Dublin has had 697 diagnosed cases. Beaumont Hospital has confirmed only two of its 19 wards remain unaffected by the virus. There were almost 30 new cases of the vomiting bug recorded this week in the hospital. Elective admissions have been cancelled.