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Showing posts from January, 2022

Reducing the covid-19 isolation period in England: a policy change that needs careful evaluation

How long people with covid-19 should self-isolate depends on the period for which they remain infectious. On 4 January, the US Centers for Disease Control (CDC) updated covid-19 isolation and quarantine recommendations with shorter isolation (for asymptomatic and mildly ill people) and quarantine periods of 5 days to focus on the period when a person is most infectious, followed by continued masking for an additional 5 days. 1 This policy was based on a modelling study from the United Kingdom by Bays et al which showed that after the 5th day after a positive test, an estimated 31% of persons remained infectious. 2 All the authors of this modelling study, which was published as a pre-print on 24/12/2021, work for UK Health Security Agency (UK HSA). On 22 December 2021, the UK HSA reduced self-isolation for covid-19 cases in England from 10 to 7 days following negative lateral flow tests on days 6-7. The UK HSA stated that that a 7-day isolation period alongside 2 negative lateral fl

Why the government’s new policy on face masks in England is a retrograde step

The government announced today that face masks will soon no longer be mandatory in England. Why is this a retrograde step in controlling the spread of Covid-19? Covid-19 is an infection that is largely spread indoors – particularly in crowded, poorly ventilated areas – through inhaling droplets and aerosols produced by infected people when they cough, sneeze, sing, talk, or breathe. Face masks are a simple method of reducing the risk of infection – but masks work much better if they are worn by large numbers of people. The main function of a mask is to reduce the emission of droplets from infected people into the air. The droplets are captured by the mask and hence less virus enters the air. Much of the benefit of wearing face masks goes to other people but they can also benefit the wearer, particularly if a high-specification FFP2 mask is worn that filters out more particles and droplets when the wearer breathes in air. Wearing face masks will reduce the spread of the coronavirus and

What percentage of people remain positive after a diagnosis of Covid-19?

The recent change in isolation policy for people in England was based on a modelling study by Bays et al which showed that “after the 5th day after a positive test, an estimated 31% of persons remain infectious”. Reference:  Bays D, Whiteley T, Pindar M, et al. Mitigating isolation: The use of rapid antigen testing to reduce the impact of self-isolation periods. medRxiv 2021:2021.12.23.21268326. doi: 10.1101/2021.12.23.21268326  Bays et al Table 3 : Percentages (rounded to integer) of people who are still infectious after each day according to their disease profile   Day   0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Still infectious (%) 100 92 75 58 43 31 22 16 11 7 5 3 2 2 1 No-longer infectious (%) 0.0 8 25 42 57 69 78 84 89 93 95 97 98 98 99   Bays et al Table 4 : Output from the model of the effect of the considered scenarios on disease release into the community (measured in three different ways) and the self-isolation in addition to that which is necessary to contain disease spread. Inter

Isolation for people with Covid-19 in England: Follow the guidance carefully

The UK government has announced that people in England self-isolating because of a Covid-19 infection will be able to end their isolation period after 5 full days instead of the previous 7 days if they test negative on both day 5 and day 6 with a lateral flow test and do not have a temperature. The change comes into force on Monday 17 January 2022. What are the implications of the government’s decision to reduce the isolation period to 5 days for people in England with Covid-19? In summary, it’s a pragmatic step with some benefits but there are also some caveats and concerns that the government needs to address. A shorter isolation period will allow people to return to work, education and social activities more quickly than the previous 7-day or 10-day isolation periods that we had in England. This will help address workforce shortages in the economy and will also allow children and students to resume their education. A shorter isolation period may also lead to greater compliance, a

London is an important barometer for the omicron wave in the United Kingdom

Over the last few weeks, the United Kingdom has experienced a record number of covid-19 infections, driven by the rapid spread of the Omicron coronavirus variant, with the daily reported case numbers approaching 200,000 on some days. This has placed considerable pressure on the NHS through a combination of people seriously ill from covid-19 and staff absences. Other parts of the economy such as public transport have also been badly affected by staff absences. A sustained period of high infection rates would be very damaging for the UK. But there are now signs that the number of covid-19 cases in London – the first area of the UK to face the wave of infection from Omicron – may have peaked. In which case, a similar pattern of declining case numbers may be seen in other parts of the UK later this month. There were several factors that drove the early increase in Omicron cases in London. London is the UK’s main international travel hub with the UK’s busiest airports located nearby.

It’s time for more targeted use of lateral flow tests for Covid-19

Lateral flow tests for Covid-19 that give a result quickly are a key part of the government’s plans to manage the covid-19 pandemic in England.[1] They are required for key workers such as NHS staff; and for people following guidance from Test and Trace, either because they have a covid-19 infection or have been a close contact of a covid-19 case.  The government also announced recently that other groups of workers in essential industries would be required to carry out regular lateral flow tests .[2] This would be in addition to the tests required by other groups, such as school children. And yet, despite their potential value, the government has been distributing the tests in a very haphazard fashion; with the outcome that many groups – such as NHS staff – are complaining that they are unable to obtain tests .[3] Meanwhile, other groups of people have been using the tests excessively – including families carrying out daily tests on each family member and in some cases, carrying out