Decision will be based on how system is coping, and whether numbers are sufficiently positive

Public health officials will base any decision on the future of the restrictions after May 4th on two main sets of factors; what the numbers are telling us and how the system is coping.
We know the numbers in terms of new cases, death rates and ICU admissions are moving in the right direction; the question is whether the trend is sufficiently positive to prevent the possibility of a second wave of infection.
Tuesdays figure of 229 new cases was the lowest since April 1st; the daily number has bobbed around while generally reducing over time. The daily rate of increase is down to about 1 per cent.
Tuesday saw 59 deaths reported, one of the highest daily figures. The trend in fatalities in recent weeks has been strongly driven by the problems in nursing homes and other residential settings, which now account for 60 per cent of overall deaths. Irelands death rate is now about the same as Swedens, which had no lockdown.
Hospital admissions for Covid-19 have been flat since near the start of April. The number of confirmed cases in critical care beds has fallen from a high of 160 on April 9th to 113 this week.
With at least half of ICU standing capacity unused, even before account is taken of hundreds of surge capacity beds, it is clear the hospital system has been able to deal with the first wave of infection in this epidemic with some margin of comfort.
The same cannot be said of the systems ability to test people for the disease widely and quickly. Targets have been set and reset, and still the Holy Grail of 100,000 tests a week has not been reached now the target date is May 18th.
And whereas public health officials have long said they want real-time testing meaning results are returned within hours the system is taking three to four days to deliver a result after a test has been sought, and an average of six days to complete contact tracing.
An overall index of performance in an epidemic is the R0 or reproduction number, a measure of how many other people a person with the disease goes on to infect. This needs to be below 1 so that each case infects fewer than one other person for the epidemic to start dying out.
Irelands R0 has been below 1 for several weeks now, and currently stands at a little over 0.5. This figure should allow for the easing of measures, yet Irish officials seem nervous about the reliability of this indicator.
Germany, with an R0 of 0.9, is easing measures in many states, as is the UK, where the figure stands at about 0.7.
Research at the University of Auckland in New Zealand shows Ireland, along with other countries, succeeded in reducing R0 significantly through the imposition of restrictive measures.
However, our reduction was one of the lowest of the 16 countries surveyed. While in part this is because Irish restrictions have been in place for a shorter period, the data shows we under-performed against countries such as Norway and Iceland, where the disease has followed a similar time trajectory to our own.
In general, faster implementation and longer duration of restrictive measures yielded the greatest reductions in R0, the research found. The contrast with New Zealand, which has throttled the disease on the back of a quickly-imposed ban on international travel, and Ireland, which has largely shied away from interfering with the free movement of people, is salutary.
One of the problems facing anyone trying to analyse Irelands performance is the lack of information available. Key data for example on testing or deaths is often served up at National Public Health Emergency Teams (NPHET) daily briefings but is not published in a coherent fashion.
New Zealand, in contrast, publishes detail on individual clusters and even cases, down to flight numbers where travel was involved. It also releases figures on lab testing and capability, and an ethnic breakdown of cases.
Here, it is hard to get a sense of what is really going on in the community from the information provided. The massive rise in outbreaks in care settings has been documented, but this has limited ramifications for the wider community, so long as staff exposed to the virus are properly monitored.
Worryingly, two-thirds of transmission of the virus is in the community New Zealand classifies only 4 per cent of its cases as of unknown source yet no granular detail about these cases is provided. Are these clusters occurring in a particular ethnic group, for example? Or group of workers? Or geographical areas?
Overall, the figures suggest some easing of restrictions is possible, though the number of new cases is a worry and the situation would have to be monitored closely for any resurgence of the virus. For the time being, however, problems with testing and worries over the ongoing supply of protective equipment for healthcare workers are likely to tip the decision against any major loosening of the restrictions.