By Sheriffah Noor Khamseah Al-Idid Dato Syed Ahmad Idid
RESPECTED Prime Minister, Health Ministry (MOH) and National Security Council (NSC) officials, it is with due respect and as a concerned citizen that I would like to make a reference to a study conducted by researchers from my alma mater, the Imperial College, University of London, United Kingdom.
The report entitled “Non Pharmaceutical Interventions (NPIs) to reduce COVID-19 mortality and healthcare demand , launched in March 2020” , based on epidemiological modelling had considered the impact of five different non-pharmaceutical interventions (NPI) – case isolation in the home, voluntary home quarantine, social distancing of those over 70 years of age, social distancing of entire population and closure of schools and universities – implemented individually and in combination and describes the cost of inaction; in the (unlikely) absence of any control measures or spontaneous changes in individual behaviour, the team would expect a peak in mortality (daily deaths) to occur after approximately three months.
This report highlighted that two fundamental strategies are possible:
Suppression
Here the aim is to reduce the reproduction number (the average number of secondary cases each case generates), R, to below 1 and hence to reduce case numbers to low levels or (as for SARS or Ebola) eliminate human-to-human transmission.
The main challenge of this approach is that NPIs (and drugs, if available) need to be maintained – at least intermittently – for as long as the virus is circulating in the human population, or until a vaccine becomes available. In the case of COVID-19, it will be at least a 12 to 18 months before a vaccine is available. Furthermore, there is no guarantee that initial vaccines will have high efficacy.
Mitigation
Here the aim is to use NPIs (and vaccines or drugs, if available) not to interrupt transmission completely but reduce the health impact of an epidemic, akin to the strategy adopted by some US cities in 1918, and by the world more generally in the 1957, 1968 and 2009 influenza pandemics.
In the 2009 pandemic, for instance, early supplies of vaccine were targeted at individuals with pre-existing medical conditions which put them at risk of more severe disease. In this scenario, population immunity builds up through the epidemic, leading to an eventual rapid decline in case numbers and transmission dropping to low levels.
The strategies differ in whether they are aimed at reducing the reproduction number, R, to below 1 (suppression) – and thus cause case numbers to decline – or to merely slow spread by reducing R, but not to below 1.
When examining mitigation strategies, the report assume policies are in force for three months, other than social distancing of those over the age of 70 which is assumed to remain in place for one month longer. Suppression strategies are assumed to be in place for a minimum of five months or longer.
Mitigation is aimed at reducing the impact of an epidemic by flattening the curve, reducing peak incidence and overall deaths. Since the aim of mitigation is to minimise mortality, the interventions need to remain in place for as much of the epidemic period as possible.
Introducing such interventions too early risks allowing transmission to return once they are lifted (if insufficient herd immunity has developed); it is therefore necessary to balance the timing of introduction with the scale of disruption imposed and the likely period over which the interventions can be maintained. In this scenario, interventions can limit transmission to the extent that little herd immunity is acquired – leading to the possibility that a second wave of infection is seen once interventions are lifted.
Mitigation strategy scenarios for GB showing critical care (ICU) bed requirements. The black line shows the unmitigated epidemic. The green line shows a mitigation strategy incorporating closure of schools and universities; orange line shows case isolation; yellow line shows case isolation and household quarantine; and the blue line shows case isolation, home quarantine and social distancing of those aged over 70. The blue shading shows the three month period in which these interventions are assumed to remain in place.
The report above highlighted the predicted relative impact on both deaths and ICU capacity of a range of single and combined NPIs interventions applied nationally in GB for a three-month period based on triggers of between 100 and 3,000 critical care cases. (see Figure 1).
Conditional on that duration, the most effective combination of interventions is predicted to be a combination of case isolation, home quarantine and social distancing of those most at risk (the over 70s). mortality. In combination, this intervention strategy is predicted to reduce peak critical care demand by two-thirds and halve the number of deaths.
However, this “optimal” mitigation scenario would still result in an eight-fold higher peak demand on critical care beds over and above the available surge capacity in both GB and the US.
Choice of suppression over mitigation
Given that mitigation is unlikely to be a viable option without overwhelming healthcare systems, suppression is likely necessary in countries able to implement the intensive controls required. The report’s projections show that to be able to reduce R to close to 1 or below, a combination of case isolation, social distancing of the entire population and either household quarantine or school and university closure are required (Figure 2, Table 1). Measures are assumed to be in place for a 5-month duration.
All four interventions combined are predicted to have the largest effect on transmission (Table 1). Such an intensive policy is predicted to result in a reduction in critical care requirements from a peak approximately three weeks after the interventions are introduced and a decline thereafter while the intervention policies remain in place. While there are many uncertainties in policy effectiveness, such a combined strategy is the most likely one to ensure that critical care bed requirements would remain within surge capacity. (see Fig 2)
Figure 2: Suppression strategy scenarios for GB showing ICU bed requirements. The black line shows the unmitigated epidemic. Green shows a suppression strategy incorporating closure of schools and universities, case isolation and population-wide social distancing beginning in late March 2020. The orange line shows a containment strategy incorporating case isolation, household quarantine and population-wide social distancing. The red line is the estimated surge ICU bed capacity in GB. The blue shading shows the 5-month period in which these interventions are assumed to remain in place.
Combining all four interventions (social distancing of the entire population, case isolation, household quarantine and school and university closure) is predicted to have the largest impact, short of a complete lockdown which additionally prevents people going to work.
Once interventions are relaxed infections begin to rise, resulting in a predicted peak epidemic later in the year. The right panel of Table 1 shows that social distancing (plus school and university closure, if used) need to be in force for the majority of the 2 years of the simulation, but that the proportion of time these measures are in force is reduced for more effective interventions and for lower values of R0.
Table 1: Suppression strategies for GB. Impact of three different policy option (case isolation + home quarantine + social distancing, school/university closure + case isolation + social distancing, and all four interventions) on the total number of deaths seen in a 2-year period (left panel) and peak demand for ICU beds (centre panel). Social distancing and school/university closure are triggered at a national level when weekly numbers of new COVID-19 cases diagnosed in ICUs exceed the thresholds listed under “On trigger” and are suspended when weekly ICU cases drop to 25% of that trigger value. Other policies are assumed to start in late March and remain in place. The right panel shows the proportion of time after policy start that social distancing is in place. Peak GB ICU surge capacity is approximately 5000 beds. Results are qualitatively similar for the US.
As COVID-19 progresses, countries are increasingly implementing a broad range of responses. The Imperial College’s study demonstrate that it will be necessary to layer multiple interventions, regardless of whether suppression or mitigation is the overarching policy goal.
However, suppression will require the layering of more intensive and socially disruptive measures than mitigation. The choice of interventions ultimately depends on the relative feasibility of their implementation and their likely effectiveness in different social contexts.
Recommendations for Malaysia
In view of the very high COVID-19 cases currently experienced by Malaysia, I would like to offer the following recommendations:
- Malaysia to reinstitute the current MCO 3.0 following the same strict and tight restrictions as imposed during MCO 1.0, which is self-quarantine, wear masks, adopt social distancing, restrict mass movement and large gatherings, close schools and universities as well as non-essential businesses.
- Require social distancing of (now may be necessary) of more than one metre. Many places now require 1.5 metres and some countries in Europe recommends two metres.
- Arising from confusion over Malaysian and International citizens and businesses of the changing SOPs for the several types of lockdown (MCOs, CMOs, EMCOs and RMCOs), it is best for the Government to just institute a nationwide MCO with same restrictions to ensure clarity to all and effectiveness in mitigating COVID-19
- As a support of Health Ministry director general Tan Sri Dr Noor Hisham Abdullah’s efforts to share videos on dire situation of COVID-19 patients in hospitals, the Government could request public and private media companies to share this and other related conditions on national media, to convey the seriousness of this pandemic to a wider audience.
- As priority must be offered to lives, sufficient support too needs to be provided to businesses, owners as well as employees to improve livelihoods. – May 15, 2021.
Sheriffah Noor Khamseah Al-Idid Dato Syed Ahmad Idid is contributor to FocusM.
The views expressed are solely of the author and do not necessarily reflect those of Focus Malaysia.
