– Dr Shivam Jasrotia
The novel coronavirus (2019-nCoV) that emerged in Wuhan, China in December 2019 now spread throughout the world. It is thought to be primarily transmitted by respiratory droplets with a similar generation time and incubation time as SARS coronavirus (SARSCoV) [1, 2].
It has been proved to be an important topic throughout human history to control the spread of infectious diseases such as the plague [3, 4] or the Spanish flu [5] [6]. Due to the worldwide outbreak of the coronavirus disease 2019 (COVID-19) induced by the novel coronavirus SARS-CoV-2, it is of particular interest in the present time [7, 8].
Since now vaccines and antivirals are absent for this, only rigorous implementation of traditional public health measures can bring some remarkable achievement in this regard. The primary goal of such public health measures is to prevent person-to-person spread of disease by separating people to interrupt transmission. So this time we are only equipped with isolation and quarantine, social distancing and community containment which are currently being employed at an unprecedented massive scale throughout most of the world. Let us know how they are being used to control the novel coronavirus and what would be their challenges and benefits.
To interrupt the transmission, isolation of patients is found effective that too if there is possibility of early detection before overt viral shedding. Moreover, if we talk about influenza patients, they can already transmit the same before clinical symptoms set it; and to halt transmission and control an influenza pandemic, isolation is often too late to be sufficiently effective. However, the incubation time for SARS CoV is longer than for influenza (about 5 versus 2 days) [9], and once the patient is truly sick, the viral shedding was found to be the highest. A longer incubation time is required to identify cases and then to put them into isolation. Incubation time for 2019-nCoV also has a median of 5 days [10], however, shedding of virus and its peak transmissibility at this stage still remains unknown and how frequently pre-symptomatic cases result in secondary cases.
One of the most effective and oldest methods of controlling communicable disease outbreaks is ‘quarantine’. In Italy, in the fourteenth century this public health practice was widely used, when ships from plague-infected ports were arriving at the Venice port and they had to anchor and wait for 40 days (in Italian: quaranta for 40) before disembarking their surviving passengers[11]. The provided forty days incubation time is enough to be completed so that cases which are yet asymptomatic became symptomatic and could therefore be identified. There was a successful implementation of quarantine during the SARS epidemic in 2003 as an effective measure [12]. It may be applied at the individual or group level and usually involves restriction to the home or a designated facility. It may be voluntary or mandatory. During this duration, all the individuals should be monitored for the occurrence of any symptoms associated with it. If such symptoms occur, People must be immediately isolated if they are found symptomatic in a centre designated for that purpose and is familiar with treating severe respiratory illness[13].
In a broader community, where individuals may be infectious but have not yet been identified so they have not been isolated yet and in such a community ‘social distancing’ is designed to reduce interactions between people. Since if some disease is to be transmitted through respiratory droplets. It requires a close proximity of people, so social distancing among persons will reduce transmission. It has been observed that the occurrence of social distancing is particularly useful in settings where community transmission is believed to have occurred, but where there is unclear linkages between cases. It is also useful in cases where persons are under restrictions and those persons were known to have been exposed and this act of social distancing is considered insufficient to prevent further transmission [14]. So by keeping all this in mind we can include closure of schools, offices and suspension of public markets and cancellation of social gatherings whether at religious places or anywhere else under this umbrella term “social distancing”.
Then after that ‘communitywide containment’ may need to be implemented, if these measures are considered to be insufficient. It is an intervention applied to an entire community, region, city and is designed to reduce personal interactions where minimal interactions with respect to ensure vital supplies are allowed only. It is a continuum to move ahead from social distancing to community-wide quarantine with major movement restrictions of everyone. During such community-wide quarantine, Moreover it is particularly important to use the social media widely during such community wide quarantine since the social media provides an opportunity for communicating about quarantine, reassurance and practical advice along with knowledge of false rumours and panic[13].
Even a study done by Kissler et al 2020 [15] revealed that a single period of social distancing will not be sufficient to prevent critical care capacities from being overwhelmed by the COVID-19 epidemic, because a rebound in the transmission may occur again after the end of the period as single period of social distancing will leave enough of the population susceptible to that thus ultimately it will lead to an epidemic that exceeds this capacity and if it coincides with a wintertime, resurgence could be especially intense.
Intermittent social distancing can maintain the prevalence of critical COVID-19 illness within current capacities, but this strategy could prolong the overall duration of the epidemic into 2022. Increasing critical care capacities would substantially reduce the overall duration of the epidemic while ensuring adequate care for the critically ill.
Moreover, early implementation of strong social distancing is found essential for controlling the spread of this SARS-CoV-2 and also when there is absence of preventive measures or new therapies such as aggressive case finding and quarantining [16], the only way may be the intermittent distancing measures to avoid overwhelming critical care capacity while building population immunity.
According to the data from 1918 influenza pandemic in the United States[17],it has been observed that the strong social distancing can lead to especially large resurgences in which the size of the autumn 1918 peak of infection was found inversely associated with that of a subsequent winter peak after when the interventions were no longer in place[15]. It will be necessary to carry out widespread surveillance to implement an effective intermittent social distancing strategy just to monitor when the prevalence thresholds that trigger the beginning or end of distancing have been crossed.
Critical care bed availability might be used as a proxy for prevalence without such surveillance, but this metric is far from optimal since the lag between distancing and peak critical care demand could lead to frequent overrunning of critical care resources. Under some circumstances, intense social distancing may be able to reduce the prevalence of COVID-19 enough to warrant a shift in strategy to contact tracing and containment efforts, as has occurred in many parts of China[16,18,19]. Still those countries that have achieved this level of control of the outbreak should also prepare themselves for the possibility of substantial resurgences of infection and a return to social distancing measures, especially if seasonal forcing contributes to a rise in transmissibility in the winter.
To maintain control of the epidemic, treatments or vaccines for SARS-CoV-2 that would reduce the duration and intensity of social distancing are required. The proportion of infections that require critical care can be reduced by such treatments and even they could also reduce the duration of infectiousness, which ultimately lead to the reduction of demand for critical care resources.
A vaccine would accelerate the accumulation of immunity in the population, reducing the overall length of the epidemic and averting infections that might have resulted in a need for critical care. A period of sustained or intermittent social distancing will almost certainly be necessary because the development and widespread adoption of pharmaceutical interventions will still take months at its best [15].
However, it is believed that its elimination is unlikely by taking into consideration the widespread transmission of SARS-CoV- 2 so there would be sufficient re-introductions of SARS-CoV-2 from locations with ongoing outbreaks initiate sustained local transmission again [20]. Still there is insufficient serological data to assess the amount of immunity that exists to SARS-CoV-2 and its duration. If SARS-CoV-2 immunity wanes rapidly, social distancing measures may need to be extended longer.
However, if there are many undocumented asymptomatic infections that lead to immunity [21], less social distancing may be required. Social distancing strategies will require further evaluation as longitudinal serological studies clarify the extent and duration of immunity to SARS-Cov-2 [15].
The spread of this disease is difficult to control, since the majority of infections are not detected [22]. Due to the lack of vaccines, attempts have been mainly focused on social distancing [23, 24] and quarantine [25, 26] to control the pandemic, means the general reduction of social interactions, and in particular the isolation of persons with suspected or actual infection is required now [27].
Finally, I conclude by saying that India, being the second most populous country in the world, must need to put focus on social distancing and quarantine like measures rather than coming in contact with one another on frequent means, so as to be on safer side from being affected by this most contagious disease COVID-19 until some exact vaccine for this disease be proved true to its best.
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