Summary of Department of Health paper to NI Executive, 19 November, 2020
In summary, with schools open and the current restrictions, Rt has settled at around 1, meaning that we are in an approximate equilibrium with regard to community transmission of the virus. There has been a reduction in cases per day of around 50% since the onset of restrictions, but numbers of cases, admissions, hospital inpatients, ICU occupancy and deaths remain at a relatively high level. In particular, hospital inpatients are at a higher level than was reached in wave 1 and are declining only very slowly. As a consequence the hospital system and staff remain under very high pressure.
It is highly likely that the planned relaxations of the next 2 weeks will result in Rt rising significantly above 1, with a subsequent increase in cases, admissions, inpatients, and ICU occupancy becoming apparent in December. This increase in transmission will occur from a relatively high baseline.
If no action is taken the hospital system will be at risk of becoming overwhelmed in mid-late December. Planned activity, some of which will be urgent in nature, will need to be downturned or stopped altogether to allow COVID patients to be cared for. There will be a significant increase in both COVID and non-COVID deaths.
It is also likely that even a full lockdown beginning around the 14 December would be insufficient to prevent current levels of hospital pressure being significantly exceeded.
Relevant considerations to respond to increased transmission:
Use of mass testing:
There has been considerable interest in the potential of mass testing to reduce transmission of the virus. However, it is important to recognise that this is largely based on theoretical considerations and there has been as yet no clear demonstration anywhere in the world that mass testing can significantly reduce transmission in a short period against the background of a high level of community transmission.
Modelling suggests that repeated mass testing of most of the population would be required to maintain control of transmission by this means. This would require a very high degree of population buy in and would present huge logistical challenges. Both Slovakia and Liverpool have required military logistical support to deliver their programmes and at least a two week run in before testing was implemented. It remains unclear whether the required number of tests would be available to NI. The Health Minister has written to the Secretary of State for Health Matt Hancock to request four million rapid Lateral Flow Device tests for Northern Ireland.
At present, given the uncertainties discussed above, reliance on mass testing alone (i.e. in the absence of significant other restrictions) would represent a high risk approach in the run up to Christmas. In addition, it may not be feasible for logistical or test supply reasons.
There may be scope to target more limited mass testing to high risk areas; this would be of help but, again, would not avoid the need for NI wide restrictions at this time.
Enhanced adherence and enforcement in relation to existing measures:
Both incentives and penalties / enforcement have a role to play in reducing transmission of the virus, and this is being taken forward separately. While this will be of benefit, there is little evidence to expect it will have sufficient impact to reduce virus transmission to the required degree on its own.
Increased hospital capacity
In theory, measures to increase hospital capacity would allow an increased epidemic level to be managed, but this would inevitably be associated with increased deaths and might be limited by the need of staff to self-isolate as a consequence of healthcare related outbreaks in hospitals or clusters and outbreaks in the community. It is also the case that the associated levels of community transmission would inevitably result in a further significant increase in outbreaks in care homes among extremely vulnerable older people as was experienced in the first wave, which will result in excess deaths in this population.
However, for practical purposes it is simply not possible to increase hospital capacity in the short to medium term. The key factor here is the supply of staff, and given the specialist skill set required, there is a very long lead time for this. While some marginal gains in capacity can be made in specific areas (e.g. ICU), this comes at the cost of reduced capacity elsewhere in the system, as it involves the redeployment of existing staff. In addition, when doubling time for cases is 7-10 days, even a doubling of hospital capacity (unlikely to be achievable) would buy only a limited period of relief before intervention was required.
There is no doubt that a successful vaccination programme represents the best exit route from the current epidemic. Early results from vaccine trials (Pfizer and Moderna) are very encouraging, and we remain optimistic that some vaccine doses will be available for the Pfizer vaccine in December. However, it is important to recognise that this vaccine requires the administration of two doses at least four weeks apart, and that immunity (when achieved) will not be apparent for 4-5 weeks after the administration of the first dose. Therefore, there is no possibility that vaccination will obviate the need for additional measures / intervention before Christmas.
Test, trace, protect:
The Executive has been advised previously of the extensive developments which have taken place in the TTP service to improve capacity and efficiency and maximise impacts on transmission. We will continue to build on these developments, including enhanced / reverse contact tracing. However, it is important to recognise that no TTP service can successfully suppress transmission when community transmission is at a high level. For example, the system in Germany (widely considered to be the best in Europe) was unable to cope due to infection levels far lower than those in NI. In this context TTP will not be able to sufficiently suppress community transmission in the absence of additional restrictions.
In summary, the advice of CMO and CSA was that additional intervention in the form of restrictions was required before Christmas to avoid the risk of the hospital system becoming overwhelmed. Two weeks of restrictions beginning on 27 November was the recommended option in terms of reducing virus transmission.