In the UK prince Charles, Matt Hancock and others who get COVID-19 isolate for only 7 days. Yet the WHO say to isolate until all the symptoms resolve plus 14 days.

25 professors of public health, virology, immunology etc have signed a letter asking the UK government to share the evidence for their much shorter isolation period.

The long isolation period for COVID-19 should come as no surprise after SARS. For SARS the isolation period required by the CDC in the US is until 10 days after the resolution of fever, provided respiratory symptoms are absent or improving

COVID–19 seems to be infectious for as long as SARS or longer.

So why is the UK only isolating for 7 days? No evidence for this has ever been presented. The UK shortened isolation from the WHO recommended period to 7 days when it switched to the delay phase on March 12th, but it did not give any public rationale for this change.

Here is Dr Nisreen Alwan’s tweet where she shares the open letter

This is what the WHO say

For mild laboratory confirmed patients who are cared for at home, to be released from home isolation, cases must test negative using PCR testing twice from samples collected at least 24 hours apart. Where testing is not possible, WHO recommends that confirmed patients remain isolated for an additional two weeks after symptoms resolve and monitoring should continue for the duration of home care.

Home care for patients with COVID-19 presenting with mild symptoms and management of their contacts

NHS say:

Evidence suggests that people who develop symptoms are very unlikely to pose an infection risk to other people beyond the 7th day of illness, so these people can return to some of their normal activities at this point but must continue to abide by the advice for everyone to stay at home that has been issued by the Government to the entire population.

Stay at home: guidance for households with possible coronavirus (COVID-19) infection

What is this evidence? Why has it not been shared with the UK public, or indeed with the WHO and the world?

NHS do say that if your fever persists you need to self isolate for as long as you have a fever - but not if your fever is gone and you still have a cough.

If you have symptoms of coronavirus, you'll need to self-isolate for 7 days.

After 7 days:

  • if you do not have a high temperature, you do not need to self-isolate
  • if you still have a high temperature, keep self-isolating until your temperature returns to normal

You do not need to self-isolate if you just have a cough after 7 days. A cough can last for several weeks after the infection has gone.

Self-isolation advice - Coronavirus (COVID-19)

The WHO period is for two weeks after all symptoms resolve, so that would include the entire period you have a cough plus 14 days.

Here is a meme I did for sharing which summarizes the issues:

Text: UK Professors request scientific evidence for UK's ultra short Covid-19 isolation period

WHO isolation ends 14 days after symptoms resolve

Before I continue, a reminder, you can protect yourself from this virus. You need to do thorough hand washing and avoid touching your face as well as physical distancing. These measures work, for instance Maria van Kerkhove and Bruce Aylward of the WHO used them to stay safe from the virus when they joined the team researching the Chinese response, visiting the worst COVID-19 hot spots in China in the middle of their outbreak.

The WHO were asked about their isolation period recommendations again in their press briefing on 13th April. Maria van Kerkhove repeats that their advice is still through to 14 days after symptoms resolve, or two negative PCR tests 24 hours apart:

At 43:38

MK If I could say what our policy actually is it may be helpful and this is based on the science that we have. What the WHO recommendations are are for someone who tests positive for COVID-19 with a PCR test, what we recommend is for them to be released from either hospital or home isolation is that their symptoms resolve and they have two negative PCR tests 24 hours apart.

We realise that that may be difficult in many situations where lab testing may be challenged for one reason or another so in situations where tests are not available if you have someone at home that's a suspect case, a probable case and couldn't get tested what we recommend right now is that those individuals are in home isolation if they can't be isolated in a medical facility until their symptoms resolve plus an additional 14 days.

They are looking at the available data to see if that 14 days extra period can be reduced.

What we're trying to do right now is look at that 14-day extra period to see if that's something that can be reduced based on available data.

She shares evidence from a preliminary small study of mild patients. She says they shed live virus eight or nine days after symptoms onset, and are PCR positive for two to three weeks. She says we don’t have the full picture yet and there are a lot of studies are underway to get these answers.

At 39:17

For individuals who are infected - your question was how long can they be contagious and that's the right question because when we actually test people who are infected with COVID19 - they have this molecular test, the PCR test and they can be PCR-positive for weeks but that doesn't actually mean that they're contagious for weeks.

What we've seen from some preliminary studies - I'm referring to a study from Germany - is among some mild patients - I believe it was eight or nine mild patients - that they could find live virus for eight or nine days after symptom onset. What we need is much more data from countries to actually be able to say, how long is someone contagious. Right now what we have are these PCR tests which suggest that people with mild disease can be PCR-positive for two to three weeks. What we need to understand is, out two to three weeks, are those people still contagious. Again this is another example where we don't have the full picture but there're a lot of studies that are underway to give us those answers and so we hope to be able to get back to you with more details on that as soon as those are available.

WHO press briefing and transcript 13th April

These are serious questions that need an answer. If COVID19 cases such as Prince Charles and Matt Hancock and others think they are no longer infectious when actually they are, they can infect others, and some of those others might die.

It also applies to our doctors and nurses. If a doctor or nurse who had COVID-19 returns to work after 7 days when actually they are still infectious, they can infect other health workers and patients.

So this really does need to be resolved and the evidence for the UK’s ultra short isolation period made public.

In the letter then the professors refer to evidence of a risk of infection for 10 to 24 days after symptom onset. They also refer to evidence of viral shedding (which might not necessarily be infectious) in one case through to 37 days after symptom onset.

These figures are not surprising - they are similar to SARS,

For SARS coronavirus, viral RNA is detectable in the respiratory secretions and stools of some patients after onset of illness for more than 1 month, but live virus could not be detected by culture after week 3

Understanding COVID-19: what does viral RNA load really mean?

This is the letter:

We, the undersigned, are concerned with regards to the discrepancy between UK and WHO guidance on the period of self-isolation following symptom onset and/or lab diagnosis with SARS-CoV-2, as well as the guidance on symptoms requiring self-isolation. Current UK guidance recommends seven days of self-isolation from symptom onset; the WHO recommends 14 days of self-isolation after symptom resolution.

NHS England guidelines state: “If you have symptoms of coronavirus infection…. do not leave the house for 7 days from when your symptoms started.”

The WHO recommendations state: “For mild laboratory-confirmed patients who are cared for at home, to be released from home isolation, cases must test negative using PCR testing twice from samples collected at least 24 hours apart. Where testing is not possible, WHO recommends that confirmed patients remain isolated for an additional two weeks after symptoms resolve.”

The available literature is suggestive of a risk of infection beyond seven days from symptom onset. This has been reported to range from day 10 of symptoms to up to 24 days after symptom onset. A study published in The Lancet found the longest observed duration of viral shedding to be 37 days after symptoms onset in one participant.

We therefore wish to know the rationale behind the UK’s seven day self-isolation guidance, and whether there are plans for PCR testing to be used to determine when individuals can leave self-isolation.

They end with request for more details about PCR testing. The antibody tests can’t substitute for PCR tests as they only show whether you have antibodies to the virus and can’t determine if you are no longer shedding virus.

PCR testing is available across numerous public, private and academic institutions in the UK. We appreciate the logistical and administrative hurdles that must be overcome to utilise these facilities, along with the global supply chain issues. However, given the importance of PCR testing as a key element in the strategy to navigate away from the need for further enforced lockdowns, we request more granular detail on your five pillar plan, specifically with regards to PCR testing capacity including how much of the 100k target will be PCR tests (given that we need PCR, rather than serological-based testing for the ‘test and trace’ approach).

They also are concerned that the criteria for self isolation of mild cases based on symptoms rather than tests are not broad enough.

We are also concerned about the narrow spectrum of symptoms the UK is using as an indication for self-isolation. Initial data demonstrate that other common symptoms include sore throat, fatigue, shortness of breath, and myalgia and we are aware that other countries are using a broader range of symptoms for self-isolation.

We therefore request that the evidence base informing the UK government strategy on self-isolation (both symptoms requiring self-isolation and length of time for self-isolation) be made publicly available, and that more granular detail be provided on your five pillar plan, specifically with regards to PCR testing.

They then ask the government to make public the evidence base for their policy as well as more details for their PCR plans.


I would like to mention another major difference between UK and WHO policy - this is on home isolation.

Many people in the UK including carers, social workers, nurses and doctors are home isolating along with their household whenever a member gets symptoms of COVID-19.

The WHO do say that this can be done in cases where there aren’t hospital beds or hotels or stadiums for the mild cases - but their requirements for home isolation are far stricter than the UK guidelines.

This again can put people at risk of getting COVID-19 unnecessarily.

Home isolation

WHO: Others likely not infected yet
Clinician inspects home.
Patient and carer need clinical masks
Other stringent precautions
Maintain connection with health care
until symptoms resolve
Isolation is for duration of symptoms
+ 14 days

NHS: All isolate together

All likely infected already
Take some precautions
Especially try to protect vulnerable
(but they will probably get it anyway)
Isolation is for 7 days from start of
symptoms or as long as fever lasts.
Household quarantine for 14 days
is to wait to see if others get infected

What is the scientific evidence for the UK policy?

Image from here: Stay at home: guidance for households with possible coronavirus (COVID-19) infection
(can’t see it on the page but google images search says it is there)

For more about this see my

All this is especially important as we move to the test, trace, isolate to exit from lockdown. It’s not going to be so effective if we isolate our COVID-19 cases for too short a period of time, and don’t isolate them adequately from other members of their household.

It also matters on an individual human level. Every case that gets infected as a result of an inadequate isolation period or an insufficiently strict home isolation is a potential death that would not happen with more stringent policies.

It also matters for our health care workers.

Text: Locked psychiatric ward in Daenam Hospital South Korea - one of their big clusterse

The virus finds chinks and gets into your health system

Image: Situation At Cheongdo's Daenam Hospital Stabilizing, Concerns Remain For Daegu

If 10% of NHS staff get COVID19
Approx 250 doctors and 140 nurses may die
several thousand need intensive care

Overlay in red text: “We must save these lives”
Coronavirus department doctor making a phone call

See my

New Zealand is the latest country to show how effective the WHO policies are if applied stringently. They hit the virus hard and fast and are now down to 10 cases per day.

2020 coronavirus pandemic in New Zealand - Wikipedia

See also my

Also looking forward at how we can exit from the lockdown:

I release this article and the graphics in it under CC by SA 4.0 - you are welcome to use this article and adapt the content so long as you attribute me as the author.