The WHO talk about contact tracing in every press briefing. They constantly stress that contact tracing iis the key to suppressing COVID-19 and then stopping it. They say that contact tracing will not just delay the peak, but suppress it and crush it right down to no new cases a day.

For some reason some countries are not paying any attention to this advice. I wonder if part of it is that not many realize what it involves, and why it is so effective for this disease? It does not mean tracking random people that you walk past in supermarkets or in the street. It is about close or prolonged contacts.

It would not work in the same way for flu, or even for SARS. It does work for Ebola and has been the key to suppressing and stopping Ebola. It also, surprisingly, works for COVID-19, which is a rather unusual respiratory disease..

So what is contact tracing?

This graphic helps to explain what it is, and why it is so effective. The contacts are often members of the same household, or close contacts who know each other well. This makes the isolation much easier than for most diseases. Just isolating cases from their own households had the potential to stop 75% to 85% of the transmission in China.

This is an article in the British Medical Journal calling on the government to resume contact tracing

Case finding, contact tracing and testing, and strict quarantine are the classic tools in public health to control infectious diseases. WHO says they have been painstakingly adopted in China, with a high percentage of identified close contacts completing medical observation.

In Singapore, Vietnam, and South Korea meticulous contact tracing combined with clinical observation plus testing were vital in containing the disease. This combined with strong measures to enforce isolation for travellers returning from high incidence areas obviated the need for a national lockdown and closure of all schools in Taiwan and Singapore.

The mathematical model used by the UK government clearly shows that rigorous contact tracing and case finding is effective: the prediction of 250 000 deaths was predicated on what would happen without contact tracing.

The reasons why tracing was stopped, against WHO recommendations, have not been published. It seems to be connected to a shift from “contain” to “delay” in the government’s action plan, when contact tracing was replaced rather than supplemented with other control measures.

Covid-19: why is the UK government ignoring WHO’s advice?

Covid-19 is infections for a very long period of time, from several days before symptoms through to up to two weeks after symptoms cease. For details see

The WHO monitor the scientific reports and they have found no evidence that COVID-19 is airborne except for certain medical procedures - unlike SARS which was shown to be airborne early on. It only transmits via the larger droplets that fall to the ground in seconds, when you cough, sneeze or speak.

Typically COVID-19 is transmitted to others in the same household, or to contacts you have close contact with or very prolonged contact. It also does it slowly. One person will only infect one in ten of their contacts even in the same house

The top priority is to isolate people in the same household. In China 75% to 85% of the transmission was in households. Stopping that alone is enough to have a significant effect in suppressing this virus.

Most of the rest is transmission to people the case knows, or are easily traced.

Cases don’t typically infect others in the street, in a lift or in a supermarket. It’s far more normal to infect others in a clinic, hospital, cruise ship, prison, or your close colleagues at work. Either you know them well or someone else has arranged an occasion where you met and the organizers are able to find them.

This is why contact tracing is so effective for COVID-19. The contacts you can identify relatively quickly by talking to the patient are the ones that are most important to isolate.

Then the long incubation period of up to 14 days and the long infectious period means that even if you find a contact days after they became infectious, you are still effectively reducing the spread.

For all these reasons, if you immediately isolate all the contacts of a case as soon as you find it, you greatly reduce the spread of this virus. This is not just theoretical, South Korea, China and others have shown it by doing it.


Text: South Korea reduced cases per day ten-fold in a fortnight
We can too
Many of its remaining cases are imported from other countries.

It was similar for China

Text: China reduced cases per day 10 fold in a fortnight
We can too

You see the effect of measures up to a fortnight or so later because of the time taken from infection to symptoms then to diagnosis.

Once we get down to a smaller number of cases, we then just need to isolate those, not the whole of society and the lock down can end soon, perhaps as soon as in the next 4 weeks or so (we would notice the effects after 2 weeks, and after 4 weeks we would have significant reductions)

Spain and Italy have done the same.

The UK can't expect to go the same way as Italy and Spain if they only do the physical distancing and don't do the case finding and contact tracing.

Italy and Spain are seeing cases per day and now even the deaths are falling, but they tested for all the mild cases and isolated them, did the contact tracing and quarantined contacts. They also protected their health care systems.

We have to do the whole package not just the lock down and the testing, if we want to succeed in the way other countries have done.

This is another article I'm writing to support people we help in the Facebook Doomsday Debunked group, that find us because they get scared, sometimes to the point of feeling suicidal about it, by such stories.

Please share this widely and especially, let's try to get the attention of decision makers in the UK, also journalists and any experts who may have the ear of politicians.


The WHO publish a series of technical documents to guide governments. See Country & Technical Guidance - Coronavirus disease (COVID-19).

The WHO currently recommends quarantining all contacts, whether or not they show symptoms, to catch them in the presymptomatic stages. If they develop symptoms they are then tested and if needs be, isolated as new cases and the process starts again

Any contacts need to be put in 14 days quarantine from the last time they were exposed to the patient.

They count as exposed if they did any of these, from 2 days before and up to 14 days after the onset of symptoms in the patient:


You can totally crush COVID19. China, South Korea have shown how. Spain and Italy are doing it now too. The WHO say this with every press briefing but the media almost never report this. To do this you test, isolate and care for cases, trace contacts and quarantine the contacts.

You don’t have to find everyone.

If you stop 75% of the transmissions you change a transmission that goes

100 cases → 200 cases → 400 cases

to one that goes

100 cases → 50 cases → 25 cases

and it soon stops.

Even if you have a million cases, you can achieve a ten fold reduction per fortnight with rigorous contact tracing. It can go down as fast as it went up.


With all the lock downs, we have a precious second window to find the confirmed cases and isolate them and quarantine all their contacts.

As Maria van Kerkhove put it, in the WHO press conference on 30th March:

Maria van Kerkhove: In some senses transmission has been taken off the streets and pushed back into family units. Now we need to go and look in families to find those people who may be sick and remove them and isolate them in a safe and dignified manner so that's what I was saying previously; the transition from movement restrictions and shut-downs and stay-at-home orders can only be made if we have in place the means to be able to detect suspect cases, isolate confirmed cases, track contacts and follow up on the contacts' health at all times and then isolate any of those people who become sick themselves.

COVID-19-virtual press conference -30 March 2020

That is possible. If we do that then the cases per day will go down rapidly. This is a golden opportunity to do this. We have far fewer contacts during a lock down which makes contact tracing easier.

We also have millions of people isolated at home who are not able to work and could help do the contact tracing as volunteers.

The isolation has to be for long enough - and isolated from others in the same household.

The Director General said this in his famous “test test test” speech, where the UK only reported the need to do lots of tests and left out the part about needing to isolate the confirmed cases

Caring for infected people at home may put others in the same household at risk, so it’s critical that care-givers follow WHO’s guidance on how to provide care as safely as possible.

For example, both the patient and their care-giver should wear a medical mask when they are together in the same room. [point 3]

People infected with COVID-19 can still infect others after they stop feeling sick, so these measures should continue for at least two weeks after symptoms disappear. [point 4]

Visitors should not be allowed until the end of this period.
WHO Director-General's opening remarks at the media briefing on COVID-19 - 16 March 2020

Detailed advice here: Home care for patients with COVID-19 presenting with mild symptoms and management of their conta


If we do get a second wave - then we just do the same again but we catch it much faster at an earlier stage.

When we turn the peak and the cases per day start going down the message is to keep up our efforts and push it all the way down to zero. Then keep alert and keep it at zero if it resurges.

This is not possible with flu but COVID-19 is a very unusual respiratory disease, different also from SARS which was airborne, and COVID-19 can be stopped in this way.

From that same press conference:

Mike Ryan: The question is how do you go down and going down isn't just about a lock down and let go. To get down from the numbers, not just stabilize, requires a redoubling of public health efforts to push down. It won't go down by itself. It will bepushed down and that's what we need countries to focus on.

What is the strategy now to put in place, the public health measures that will push down the virus after those measures may be released and then how do we take care of people better in a clinical environment to save more lives

Maria van Kerkhove: These physical distancing measures, these stay-at-home measures have bought us a little bit of time, a little window of time and that short window has to be used appropriately so that we get systems in place to look for this virus aggressively through testing, through isolation, through finding contacts, through quarantining those contacts, through caring for further patients because we will still see patients and many patients are going to still require need, to support other countries that are going to go through thus.

So, focusing on what we do now is absolutely critical to make sure we use that time wisely, we use that time effectively so that once we do reach that peak we continue to push and suppress that virus down as quickly as possible but still be ready to find additional cases should they show up. What we've seen in a number of countries in Asia where they brought this virus down, they brought this transmission down; they're now seeing repeat introductions from outside of their countries. They have not let their guard down, they're still aggressively looking for those cases as they come in and suppressing them so that it doesn't start again.

So we need to focus on the now, we need to use our time wisely and that is to aggressively find this virus and care for our patients

COVID-19-virtual press conference -30 March 2020

The video of that press conference is here.

The WHO have been saying this with every press briefing for weeks now.

This is so important and yet so many countries do not seem to understand its importance.

See my

This is extracted from my longer

See also