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expert reaction to announcement that the isolation period in England will be cut to 5 full days (dependent on negative lateral flow tests on day 5 and 6) from Monday

The Health and Social Care Secretary, Sajid Javid has announced the change to the self-isolation policy in England starting from Monday.


Dr Jonathan Stoye, Senior Group Leader and Head of the Retrovirus-Host Interactions Laboratory, The Francis Crick Institute, said:

“This change in isolation policy has been much anticipated in the last few days, in large part because it will allow a significant number of people to return to work.  However, it is perhaps unfortunate that it was announced by Sajid Javid without giving precise details about its application, particularly regarding timing, and the science underlying the decision. Further it is important to note that perhaps a third of all positive individuals will still be infectious after 5 days.  This implies it is absolutely essential that two LFT tests be performed before release from isolation and that these must give negative results so that onward transmission is reduced to a minimum.  It also means that there is no guarantee that isolation for any given individual will end at day 6.  Return to work will therefore be delayed for many.”


Dr Nathalie MacDermott, NIHR Academic Clinical Lecturer, King’s College London, said:

“Let’s be clear, the decision by the Health Secretary to reduce the self-isolation period to 5 days provided there are two negative lateral flow tests on days 5 and 6 is not a scientific decision, it is a political one. The UKHSA modelled that a 5 day isolation period followed by daily lateral flow tests for 5 days would result in 15% of those released from self-isolation still being infectious (versus 5% if a full 10 days of self-isolation were completed). It must be emphasised that it would be unwise for this decision to be applied to those who work with vulnerable members of the population in the health and care sector. The UK public would also be wise to consider not visiting vulnerable members of their families until they have cleared at least 10 days since their first positive PCR test, are completely symptom free and have tested negative on a lateral flow test on the day they intend to visit.”


Prof Lawrence Young, Virologist and Professor of Molecular Oncology, Warwick Medical School, University of Warwick, said:

“This policy is certainly not following the science. Reducing the self-isolation period to 5 days runs the risk of highly infectious people returning to work or school, particularly if people don’t use lateral flow tests as advised on day 5 and 6. The government’s own modelling data suggests that, in the absence of lateral flow testing, 31% of people will remain infectious 5 days after symptom onset or after a positive test. A recent study from Japan of 21 hospitalised cases with omicron infection who had been vaccinated has shown that peak infectiousness occurs at 3 to 6 days after diagnosis or symptom onset but found that no infectious virus was detected after 10 days.

“Reducing the self-isolation period to 5 days is a concern and can only be introduced with the strict enforcement of lateral flow testing. This is not helped by current problems with the availability of lateral flow test and with concerns about people reporting the results from these tests. It will also be important to stress that anyone ending isolation on day six should continue to be cautious – wear a face covering in crowded or poorly ventilated spaces and limit contact with vulnerable people.”


Dr Simon Williams, Senior Lecturer in People and Organisation, Swansea University, said:

“On the one hand, cutting the self-isolation period might, in theory, make it easier for people to comply with the full self-isolation period.  The longer people are asked to self-isolate the harder it is.  That said, compliance has overall been quite high with self-isolation, even when a 10-day self-isolation period was still in place.  Data from early December1, found that three-quarters of those required to self-isolate complied for the full ten days.

“On the other hand, one potential problem could be that cutting the self-isolation period might be seen by some people to send a message that Covid is less of a threat – especially against a backdrop where people are receiving messages, including from some in government, that Omicron is ‘milder’ and that now is the time to move on and ‘live with’ the virus – despite UK cases still being very high and hospitalisations having not yet significantly started to decline.  Research2 has found that one of the main factors that influences compliance to self-isolation is how worried people are about COVID-19 and how much of a threat they perceive it to be.  Cutting the self-isolation period might be perceived by some as being a sign that we should be less worried about Covid, which in turn might, in theory, lead to less motivation for some to self-isolate in the first place – particularly if the right supports are not in place or their circumstances don’t make it easy for them to do so. 

“Again, in theory, a shorter self-isolation period should make it easier for people in terms of the mental health and financial challenges posed by self-isolation.  Up to one-third3 of people reported a 10-day self-isolation was difficult for their mental wellbeing, and so, 7 and now 5 days may likely have less of an impact for some.  However, these benefits that might be had from reducing the self-isolation period need to be balanced against the potential public health costs related to any additional transmission. Recent data4 suggests that approximately that twice as many are still potentially infectious at 5 days compared to at 7 days.  Also, it will be even more important for compliance with rapid testing at the end of the self-isolation period to be high, and messaging and guidance around that needs to be clear.

“Above all, it is important that government maintain the existing self-isolation support and put in the relevant protections to enable people to self-isolate without significant financial impacts or impacts to their mental or physical wellbeing – maintaining adequate financial, emotional and practical support can help people’s motivations and capabilities to comply.”


  1. Coronavirus and self-isolation after testing positive in England: 29 November to 4 December 2021    
  2.  ‘Factors associated with adherence to self-isolation and lockdown measures in the UK: a cross-sectional survey’ by L.E. Smith et al. was published in Public Health in October 2020
  3. Coronavirus and self-isolation after testing positive in England: 29 November to 4 December 2021
  4. COVID-19 self-isolation changes: scientific summary



All our previous output on this subject can be seen at this weblink:



Declared interests

Dr Jonathan Stoye: “I am currently self-isolating following a positive test and would like to safely be able to return to work.”

None others received.

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