Summary of Effectiveness and Harms of NPIs
Summary of Effectiveness and Harms of NPIs
Summary of Effectiveness and Harms of NPIs
Key points
• Cases are increasing across the country in all age groups. The effect of opening of
schools, colleges and universities has only just begun to affect this increase. Even so,
the latest data suggests that the doubling time might be as low as 7-8 days. COVID-
19 related hospitalisations and intensive care bed usage have started to increase.
• As over 90% of the population remain susceptible not acting now to reduce cases
will result in a very large epidemic with catastrophic consequences in terms of direct
COVID related deaths and the ability of the health service to meet needs. As in the
first wave, the burden of a large second wave would fall disproportionately on the
frailest in our society, but also those on lower incomes and BAME communities.
• A package of interventions will need to be adopted to prevent this exponential rise
in cases. Single interventions are unlikely to be able to reduce incidence. If schools
are to remain open, then a wide range of other measures will be required. The short-
list of non-pharmaceutical interventions that should be considered for immediate
introduction include:
o A circuit-breaker (short period of lockdown) to return incidence to low levels.
o Advice to work from home for all those that can.
o Banning all contact within the home with members of other households
(except members of a support bubble)
o Closure of all bars, restaurants, cafes, indoor gyms, and personal services
(e.g. hairdressers)
o All university and college teaching to be online unless absolutely essential.
• Although beyond the scope of this paper, the rapid rise in cases means that a raft of
complementary measures is required to reduce transmission in care homes,
hospitals and other enclosed settings, such as prisons and hostels for the homeless.
• All these interventions listed above have associated costs in terms of health and
wellbeing and many interventions will affect the poorest members of society to a
greater extent. Measures will be needed urgently to mitigate these effects and to
achieve equity and social justice.
• The more rapidly these interventions are put in place the greater the reduction in
COVID-related deaths and the quicker they can be eased. However, some
restrictions will be necessary for a considerable time.
• Clear, consistent communications will be essential, and a consistent package of
measures should be adopted that does not appear to promote contradictory goals.
Background
The current epidemiological situation, which is set out below, indicates, however, that the
(re-)imposition of a package of measures is required urgently. The aim of this paper is to
identify a list of measures that would have the largest epidemiological impact, while
minimising social and health harms, and which could be imposed at a regional or national
level.
This document takes a population-level perspective. The benefits and harms experienced by
any one individual resulting from a course of action may be very different to that averaged
over the population as a whole. That is, policies may be beneficial to the population, but
cause costs and harms to some in society. We have attempted to highlight those areas
where harms may fall on certain sectors of society and point out that measures are urgently
needed to help mitigate these effects for individuals. Often the poorest members of the
community are more likely to experience the negative consequences of some of these
interventions. However, not taking action is also likely to adversely affect these same
individuals, as the patterns of deaths in the spring wave by deprivation indices and ethnic
groups clearly demonstrates1 2.
This document should be reviewed regularly as the epidemiological picture changes and the
evidence base for the effectiveness and harms associated with these interventions is
improved.
The latest SPI-M consensus statement suggests that R is between 1.1 and 1.4 nationally and
most local authorities have R > 1. R is a lagging indicator and describes the epidemic
situation over recent weeks. It is likely to keep rising in the short term as changes in
contacts over recent weeks result in increased cases that are picked up by our surveillance
systems.
The epidemic has been growing at a rate of between 2% and 7% per day. This implies that it
doubles every 10-20 days, but the latest data suggest that this may be as little as 7-8 days
with even quicker doubling times in some areas.
1https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/deaths/articles/corona
viruscovid19relateddeathsbyethnicgroupenglandandwales/2march2020to15may2020
2https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/deaths/bulletins/death
sinvolvingcovid19bylocalareasanddeprivation/deathsoccurringbetween1marchand31july2020
This suggests that there could be around 3000 hospital admissions per day by the end of
October (which was the peak at the start of April) unless rapid action is taken to reduce
transmission.
Given that admissions and deaths will increase for 2-3 weeks after R is bought below 1,
cessation of the current growth is required by the start of October to prevent a repeat of
the first months of the epidemic. The 3000 admissions per day at the end of October is
largely driven by the infections that occur by the first week of October. It is possible that
improvements in treatment and prevention of transmission in health and social care
settings will reduce deaths associated with infections but will not generally prevent
admissions. To reduce R from 1.6 to 0.8 would require interventions to reduce transmission
by 50% - a substantial amount.
The rate of increase in infections is expected to accelerate in the near future as the impact
of school, college and university openings, and policy changes with respect to return to
workplaces, and entertainment and leisure venues, filter through. For example, ONS data
show that rates of working from home are continuing to decline, from around 40% who
“worked from home only” at the start of June, to 20% at the start of September.
Household transmission remains the most widely recorded setting of transmission. PHE
reports secondary attack rates of around 40-50% within households, confirming the key role
the household plays in transmission. Outside the household, preliminary analysis of a recent
case-control study by PHE suggests that working in health and social care remains a risk
factor, as is working in close personal services and hospitality. Activities associated with
increased risk amongst cases include frequenting entertainment venues e.g. bars and
restaurants. Outbreaks associated with restaurants and bars have also been recorded, both
in the UK and elsewhere. Outbreaks in educational settings are leading to widespread
disruption. It is still not clear to what extent (if any) schools magnify transmission in
communities rather than reflect the prevalence within the community.
Starting point
This document addresses the (re-)imposition of further measures to curb the spread of
COVID-19. We assume that no further easements to remaining restrictions will occur over
the period that these additional measures will apply. Imposing restrictions while
simultaneously easing them would be counter-productive and pose considerable
communication challenges.
There are undoubted social, psychological and health harms associated with many of the
interventions listed here. However, there are also very large harms inherent in not acting
quickly to curb the current exponential rise in cases and hospitalisations.
Evidence for the effectiveness and harms related to individual interventions is difficult to
ascertain as packages of interventions are usually implemented together and the level of
adherence may be heterogeneous and poorly quantified. Lower levels of adherence to
interventions will erode their effectiveness. Past levels are not necessarily an accurate guide
to the levels of adherence to measures that we might expect now and into the future.
Furthermore, there will be delays between the imposition of an intervention and any effect
it may have on cases or other key indicators. Finally, the counterfactual – how many
outcomes might have occurred without that package of interventions – is difficult to
ascertain. There is a lack of randomised evidence for these packages of interventions, so the
data is often observational and routinely collected in nature, supplemented with modelled
estimates. Estimating the harms from these interventions is even more difficult, given the
breadth of possible impact on physical and mental health, education, society and the
economy. Overall, the evidence base on which to judge the effectiveness and harms
associated with different interventions is weak and so there is considerable uncertainty
around the estimates presented here.
The implementation of tightened infection control measures in all hospitals, care homes,
and other enclosed settings including regular testing of staff should be seen as a priority if
infections continue to grow. Such measures are likely to have a major impact on deaths and
hospitalisations for COVID-19. SAGE has also previously noted the risks associated with
discharging people from hospitals into the community without testing to ascertain whether
they may be infectious. However, these issues are beyond the scope of this paper.
The effectiveness of all of the measures in this document requires good communication
with the public, businesses and other stakeholders. However, good risk communication is
also an intervention in its own right – helping individuals assess and reduce their own risks
appropriately. This is out of scope of this document, but the importance of engagement,
communication and feedback cannot be overemphasised.
An effective test, trace and isolate (TTI) system is important to reduce the incidence of
infections in the community. Estimates of the effectiveness of this system on R are difficult
to ascertain. The relatively low levels of engagement with the system (comparing ONS
incidence estimates with NHS Test and Trace numbers) coupled with testing delays and
likely poor rates of adherence with self-isolation suggests that this system is having a
marginal impact on transmission at the moment. Unless the system grows at the same rate
as the epidemic, and support is given to people to enable them to adhere to self-isolation, it
is likely that the impact of Test, Trace and Isolate will further decline in the future.
Addressing these issues is beyond the scope of this document.
Individuals and organisations have adopted a range of measures to reduce the risk of
transmission. These are collectively called “COVID secure” measures and include the
use of face coverings and increased hand hygiene for individuals, and the use of
screens, social distancing, cleaning of surfaces and improved ventilation. It is likely
that these measures are having an effect at slowing the rate of transmission.
Maintaining or improving “COVID security” will be important over the coming
months, but the details of how to achieve this are beyond the scope of this work.
International travel / border screening has no direct effect on onward transmission within
the country (as opposed to seeding) and is not considered here.
The economic impact of these measures will be addressed elsewhere. This document should
be seen in the context of that accompanying analysis.
Findings
The tables in Annex 1 summarise the potential impact of the different interventions, on
transmission, severe disease and deaths from COVID-19 the potential social and health
harms from the measure and potential implementation issues.
The measures below are (i) selected based on the balance between epidemiological benefits
and health and social harms, (ii) likely each to make a non-negligible impact on R. The higher
R rises, the more of them will be needed to restore R to below 1. From a purely
epidemiological position, implementing measures as soon as possible would have the
largest effect and likelihood of bringing R back below one.
Before enacting these measures, consideration needs to be given to how long they will need
to be in place. To regain control of transmission R has to be reduced, ideally to below 1.
Releasing the measures is likely to result in R returning above 1, so the longer they are in
place (and the lower the prevalence falls), the longer before they will have to be reimposed.
Discussion
Broad impact
The “circuit breaker” can be thought of a way to reduce R to below 1 and reset the
incidence of disease to a lower level. The other measures will be necessary to maintain the
reproduction number around 1 for the coming months. Careful monitoring will be necessary
to ascertain whether further changes may be necessary. It is important to emphasise that a
low incidence of disease will not only reduce the direct harms associated with COVID-19
(e.g. deaths and hospitalisations), but also allow a safer return to more normal behaviour
and allow the health service to deliver its full range of functions as safely as possible. That is,
a low incidence will also help reduce indirect health and social harms.