Testing and tracing contacts


Sir, – The discussion of Covid-19 is going round and round, dominated by lockdown and the end of lockdown, as if lockdown were the only show in town. There is some discussion of testing but little reference to what should be the main long-term reason for testing – driving the virus into extinction.

In the absence of vaccines and anti-virals, which are many months away, there is only one strategic way of ending this pandemic: trace, test, isolate, find contacts and test and isolate them, find the next ring of contacts and test and isolate them, and so on, until no new positives are identified.

South Korea, which used this strategy from the start, reported no new community-based cases today.

We must search out and ringfence, using the words of Dr Karina Butler, every case until there are no more to be found. Meanwhile it is vital to maintain lockdown as a means of reducing the number of cases to levels that can be dealt with, not just medically, but by the labs.

There are about 500 new cases every day. Assume each has about 20 close contacts – trace them and isolate them immediately and test them, with results back in one day – not two days or 10 days. Some will be positive; identify their contacts, who should isolate themselves, and test them. It will be necessary to retest negatives before they are given the all clear. Does this policy exist? Is it being considered? In tests per day, this will initially require about 10,000 rising to 100,000 and so on, perhaps to many more, per day, to ring-fence the virus.

Since resources are limited – recent reports indicate that the authorities are aiming for 100,000 per week – and the logistics are not yet in place for a national effort, it is right to focus on long-stay care homes, where we must try to make sure that homes with no cases stay that way.

And it is of course right to test everyone working in hospitals and other places where people at high risk are congregated in close proximity, others at high risk, and other key persons – infected people must not be caring for uninfected people. But in the end we need a targeted nationwide search to close in on the virus and get rid of it.

Have plans been drawn up for a nationwide testing scheme of this kind on this scale, which is at least 10 times what has been mentioned? Perhaps my figures are very wrong and we are really on top of the challenge?

If not, have we considered involving Korean labs, which must now have spare capacity, in carrying out tests for us?

I do plead that the heroic public, our students, and our deeply wounded businesses and their employees, and so many other specific groups in the firing line, deserve some straight answers to these and related questions. – Yours, etc,


Fellow Emeritus

in Genetics,

Trinity College Dublin,

Dublin 2.

Sir, – Simple instructions were given to us weeks ago by the World Health Organisation and despite these instructions being delivered in English, they have become lost in translation.

We cannot put a date on when Covid-19 might pose no threat, although we need to live and work and learn and consume in the meantime.

We already understand social distancing and hygiene and how these measures prevent transmission.

What we want our Government and our other leaders in the medical field to do is to follow the repeated and simple instructions from the World Health Organisation without the message being lost in translation. But, if there is anything to read between the lines, it is this: test (quickly), results (quickly), isolate (quickly), contact-trace (quickly). – Yours, etc,