The coronavirus situation in Ireland is deteriorating at a faster pace than anywhere in Europe, a senior HSE official has warned.
Chief clinical officer Dr Colm Henry said the infection rate is "frightening" and the curve is moving in an almost "vertical direction".
His analysis came as HSE chief executive Paul Reid warned of "serious and dangerous" levels of transmission that could lead to a "massive surge" in hospital admissions after Christmas.
Dr Henry told the weekly HSE media briefing there could be 1,500 new confirmed cases of the virus a day by the first week in January.
He said: "We received this best or second best in Europe in terms of a 14-day incidence (rate of the virus), but in terms of our deterioration over the past week, we're deteriorating at more rapid pace in seven days than any other country in Europe and so we won't hold this position for long."
Mr Reid added: "From our perspective and the HSE, the transmission levels have now reached what I would call very serious and dangerous levels of transmission.
"We have as many concerns now as we would have had in the first phase about the potential impact on what we're seeing and the transmission levels and the potential impacts looking ahead for health services.
"We see the worst culmination coming together of the rapidly rising cases at an exponential rate, combined with high positivity levels we are seeing coming through our community testing, and that too combined with increasing levels of contacts and what we know will happen in the coming days of further increasing levels of contact.
"Our particular concern relates to that this will all culminate at the same time on the same days that we know we have our high peak - days after Christmas just after Stephen's day, the 28th right through to early January.
"Our concern is the lag effect of what we're seeing coming right now impacting hospitalisations potentially post-Christmas and equally coming at a time when we know we face into our highest level of demand for health services."
Mr Reid urged people not to react to the assessment with "fear and distress" and instead take positive action to limit their contacts over the Christmas period.
He also struck an optimistic note in terms of the Pfizer vaccine rollout in Ireland.
He said the first 9,750 doses are due on December 26, with another consignment of 31,000 jabs days later. Ireland will then be in line to receive 40,000 doses a week through January and February, he added.