The Indian variant of Covid-19 could pose a risk to reopening plans, chief medical officer Dr Tony Holohan.
Speaking this afternoon, Dr Holohan said the National Public Health Emergency Team (Nphet) is closely monitoring variants of concern and is “concerned” about possible higher transmissibility of the virus.
There is particular concern about the 'Indian' variant due to its spread in other countries as well as early reports of its impact on vaccine effectiveness.
A total of 72 cases of the Indian variant (B.1.617.2), have been identified in Ireland to date.
A further 524 cases of Covid-19 were confirmed by Nphet this evening.
As of 8am this morning, there are 107 Covid patients in hospital, of which 38 are in ICU. There have been 19 additional hospitalisations in the past 24 hours.
The CMO said the public are currently keeping the virus under control while the HSE is increasing the number of people vaccinated every day.
However, he warned that the Indian variant is "a big black cloud on the horizon."
Dr David Nabarro, a Special Envoy on Covid-19 for the WHO, has said he believes the variant will grow here.
He said that the incidence of the variant will increase and it will be necessary to occasionally restrict movement and introduce widespread testing.
Some immunologists believe vaccines should still protect against the mutation.
The boss of BioNTech has said the Covid vaccine it has developed with Pfizer is likely to be as effective against the Indian variant as it is the South African one.
A scientific paper recently found the jab to be around 75% effective against that strain.
Virologist Dr Cillian de Gascun encouraged people to remain vigilant and adhere to public health guidelines given the size of Ireland's unvaccinated population and the apparent transmissibility of the variant.
Nphet chair, Professor Philip Nolan, said he is confident that if we can continue to limit transmission through individual behaviour, the vaccination effect will lead to further easing of measures in the near future.
Prof Nolan said the health service has been monitoring the key indicators of the disease and the numbers of people admitted to hospital and ICU are stable. The daily incidence is also stable.
Recent data shows an increase in the number of people going to work, visiting home and meeting people from outside their household and so there has been an increase in the number of close contacts.
Such an increase is expected as restrictions lift and society begins to reopen.
Data from the ESRI has shown that these increases are much stronger among people who have been vaccinated.
Professor Pete Lunn, Behavioural Research Unit, ESRI, said most people who are not yet vaccinated are continuing to be cautious.
"Our data is consistent with the majority of people waiting until they are vaccinated before increasing their activity again," said Prof Lunn.
Younger people are encouraged to continue following the public health advice due to the unpredictability of the virus.
Dr Siobhán Ní Bhriain said younger people should follow all public health advice as they await vaccination to avoid any risk of Long Covid-related illness.
"While evidence around Long Covid continues to emerge, we do know that a cohort of the population exposed to Covid-19 are experiencing symptoms of fatigue, shortness of breath and other side effects months after their initial diagnosis," said Dr Ní Bhriain.