The government of Mauritius deserves a round of applause for proactively implementing a confinement programme aimed at protecting the health of the nation. In time of national disaster, we must rally around to find a common solution because the COVID-19 makes no distinction to nationality, class, race, ethnicity, royalty or political affiliation: It is time to put aside all our differences and brainstorm in a truly multi-partisan manner to reach a common goal. The common enemy is the virus and not our political or social beliefs. The government jump-start policy will have a multiplier effects if it is supplemented by a five-pronged attack: 1) implement syndromic surveillance, 2) implement hospital-based surveillance for severe cases of the disease, 3) extend active case search and contact tracing, 4) assess the effectiveness of confinement, and 5) initiate mitigation measures. Now is the critical time to intervene to save our country from imminent disasters.

Implementation of syndromic surveillance :

Syndromic surveillance, also called event-based surveillance, is monitoring of persons with probable symptoms of COVID-19 without necessarily undertaking laboratory testing. This will give an indication of the frequency of probable number of infected cases. This surveillance could be undertaken in ‘flu’ clinic, duly equipped with personal protective equipment for all staff and facility for data collection and analysis. When the confinement is lifted, the syndromic surveillance must be extended to schools and workplaces as well. This method proved to be successful in the 2009 influenza pandemic in Mauritius and is currently undertaken in many countries, including France.

Implement hospital-based surveillance for severe cases :

We must keep record of all patients admitted for respiratory distress, without testing for the virus and analyse the data in real time including use of geographical mapping. This is a useful adjunct and it indicates the number of probable cases of severe COVID-19 and the attributable excess mortality due to COVID-19. There could be cases of COVID-associated mortality that are missed by the COVID surveillance; calculation of excess mortality will buckle this gap.

Extend active case search and contact tracing :

The epidemic is progressing exponentially in Mauritius; the window of opportunity to break the chain of transmission by containment is fast closing. We are at a critical juncture to search for all cases and their contacts, irrespective of symptoms. Counting the number of persons without any symptoms will be a challenging task that can be circumvented by random testing for the virus among high-risk groups and high-risk areas: The high-risk groups include, but are not limited to, the employees of frontline and public offices including health care workers, rescue services, hotel staff, amongst others. The high-risk areas include setting where there is mass gathering such as places of worship, shopping malls and recreational facilities. In keeping with WHO recommendations, we should extend community-wide testing. Countries like Singapore, Taiwan and South Korea, which have implemented this option from the beginning of the epidemic have reaped the benefits; countries like USA, Italy and Spain which have delayed taking this option are paying a high price in human lives today.

Assess and monitor the effectiveness of confinement :

The principle of confinement is to reduce the simultaneous community-wide spread of contagion; else the accrued number of cases will invariably overwhelm the surge capacity of the health care and result in count- less avoidable deaths. Infected persons show the symptoms of the contagion on an average of 14 days; this is called the incubation period of the disease. So, when we confine a cohort of infected persons, not all members will show disease after 14 days as they will be at different stages of their incubation period at the inception: some may show it on day one, others on day 2 and so on up to day 14, just like in a relay race not all the runners reach the goal post at once.

For the sake of illustration, let us we consider the effect of confinement on a COVID-infected hypothetical cohort of 4,000 members, consisting of approximately 3,000 persons with symptoms (clinical cases) and 1,000 without any symptoms (subclinical cases). Based on the assumption that one positive case of COVID-19 can infect up to 3-4 persons, straight arithmetic tells us that at the end of the confinement we would have resulted in a maximum of 16,000 cases. If we take the extreme scenario of 1 infected person contaminating 100 susceptible persons, the expected number of infected members at the end of confinement may end up being of 400,000. But this is an improbable situation as confinement will preclude this from happening.

Furthermore, according to mathematical models developed in England and Germany, in the absence of vaccine and drugs, this virus may have to infect between 60-80% of the population to develop collective immunity, the so-called herd immunity, to stop propagation of the pandemic in a population. For the Mauritian populations this will mean that between 720,000 to 960,000 persons must contract the contagion for the epidemic to stop, else the contagion will attack non-immune persons when there is population movement since the virus will lurk in the population and is transmitted by both direct contact through cough and sneeze droplets, and indirectly by air and contaminated objects on whose surfaces it can survive from hours to days.

Our confinement cannot reach the critical level of herd immunity even if extended twice and, eventually it becomes an exercise of diminishing return depending on population cooperation etc. Therefore, it becomes imperative to assess the effectiveness of the confinement by comparing the rates of infections before and after confinement. The scenarios I have advanced are hypothetical; to get a grasp on reality it is imperative to estimate the actual reproductive rate of the virus in the Mauritian population in real time, and not from parameters borrowed from other countries. In the absence of such assessment, it would be too easy to attribute the inefficacy of the confinement to a minor recalcitrant group breaking the confinement. Obviously, this group will be too small to drive the epidemic. Therefore, in addition to confinement, it is important to institute extensive mitigation measures to supplement and jumpstart the control measures.

Initiate mitigation measures :

There comes a phase of the pandemic where the number of cases exceed the testing capacity of the country. At this point, one has to switch the operation from confinement to mitigation. Mitigation measures are twofold: reduce the source of the contagion in the community and, concomitantly protect the vulnerable groups by timely and appropriate medical care. First, the contagion is eliminated by enforcing rigorous and strict infection control procedures in different settings including heath care, public facilities, metro and public transport services, markets, supermarkets, hypermarkets, government buildings, school, recreational facilities, and places of worship. Secondly, the vulnerability of the risk groups is ensured by building the resilience of the health system to effectively respond in terms of speed of detection, transport and timely access to quality health care. China, Taiwan, South Korea have practiced this option and their success in controlling the contagion is attributed to this.

A plea for concerted action :

The COVID-19 pandemic requires a country-wide approach of all sectors, community and every individual.

The responsibility of the national government is to formulate and implement healthy public policy that resonates good governance and practice integrating the principles of equity, empowerment, all-inclusiveness and fairness in combating this scourge.

The Health Authorities must ensure protection of the vulnerable through proactive planning and procurement; protect the population including providing effective and proper protective equipment for of all health care personnel not forgetting the cleaners, attendants and drivers,

Local government and municipalities, private and public enterprises including banks, supermarkets, pharmacies, etc., must ensure the cleaning of contaminated objects and surfaces to break the chain of transmission by regularly disinfecting areas that are accessed and handled by the public,

Home-delivery service must be aware of hygienic practices to avoid contaminating essential food and medical supplies,

At the family level, we should have a contingency plan of what to do when there is suspected and confirmed case in the family and the measures of disinfection thereon,

The biggest vaccine we have for this pandemic is individual behavior, therefore every individual must perform his or her civic duty in not spreading the virus to vulnerable group through practice of personal hygiene of frequent hand-washing, practising cough etiquette and isolation and social distancing,

All media, irrespective of types, must sensitize and prepare the population responsibly and not through biased reporting that tantamount to fake-news.

We are all cross-swimming across a dangerously rising tide that will sweep many of us or near and dear ones away if we do not act collectively and responsibly.

<p style="text-align: justify;">Dr Deoraj Caussy is an independent epidemiologist offering Integrated Epidemiology Solution to a variety of contemporary issues, through <a href="https://www. drdeorajcaussy.com/" target="_blank">https://www. drdeorajcaussy.com/</a>. He is an internationally acknowledged seasoned virologist and epidemiologist having worked for the world-famous Centers for Disease Control and Prevention, with the US public health service, the World Health Organization and Adviser to the Ministry of Health, Mauritius. He has advised the health matters of 1.2 billion people for WHO, addressing such issues as control of HIV/AIDS, poliovirus eradication, arsenic contamination and successfully managed the chikungunya, and dengue epidemics and the influenza pandemic during his tenure with the local authorities.</p>