A rise in Covid-19 cases has shaken us out of our comfort zone and revealed a series of potential weaknesses in our defences against the spread of the virus.
The downward trend in infections until recently sparked hopes it was nearly defeated.
The increase in new cases may not be large - but we are again reminded that as long as the pandemic lasts we will be living on a knife edge.
A: They must be seen in the context of the previous two weeks where there was a turnaround after a drop in infections.
One of the drivers behind the increase has been travel-related infections where somebody who arrives here as a tourist or a returning holidaymaker tested positive after picking up the virus abroad.
Around 15-20pc of new cases of the virus in the last fortnight were linked to foreign travel.
A number of clusters of infection have arisen as a result.
A: Clearly many are not restricting their movements after coming here.
On Thursday, 15 of the 23 cases were linked to travel. The impression was given that public health doctors were on quite a complex journey around various parts of the country to trace contacts of at least one of the infected people who came here from abroad. The self quarantine is not mandatory so there is the potential for a repeat of this over the summer.
A: In the case of a tourist who is infected they could be in Dublin one day, Galway the next and then on a tour of Kerry. This poses a risk of spread that might be difficult to trap. People can be infected and not have symptoms, unwittingly passing it on.
A: There is plenty of capacity to test people but the puzzle is in chasing down contacts, those in close proximity for a period of time with the infected person. There was criticism of the tracing in previous months and this summer will provide a new challenge. The downloading of the Covid tracing app by around 1.1 million people will help. Users will get an alert if they are a close contact.
A: There are two tests - one at the beginning and another on day seven. But there is another weakness here which could undermine the trail to bring a cluster under control.
Around 40-50pc are not taking up the offer of a test on day seven so could be walking around with no symptoms and spreading infection.
A: Yes, they will not have to self quarantine but can go to Spain, France and Italy. The fact they may return via Dublin could add another infection risk.
A: When safety measures in place in shops and pubs are followed the risk of infection is minimised. But if the rules are flouted and people mix as they did in pre-Covid-19 times there is more scope for the virus being passed on.
A: Neither of these are mandatory and unlikely to be unless there is another dangerous surge.
A: The under-25s feature prominently in new infections.
A: It's too early to say what the impact of the revelries outside pubs seen last weekend will have on infection rates.
They are also socialising indoors and house parties have become more common. As long as they ignore the rules they will be a risk not just to themselves but more seriously to people who have weakened immune systems.
Taoiseach Micheál Martin and Health Minister Stephen Donnelly tried to get this message through yesterday but if younger age groups don't heed it this behaviour will prove another shortcoming over the summer.
A: When cases are low, as they are now, it is difficult to measure it. If it rises higher than one, it means people infected with the virus are spreading it to others at a rate faster than one to one, which could see the disease spiral out of control.
We are told there is no cause for alarm but there is need for caution.
Visit our Covid-19 vaccine dashboard for updates on the roll out of the vaccination program and the rate of Coronavirus cases Ireland