Quarantine and Isolation are public health practices to protectthe people by preventing exposure to people who have or may have a contagious disease.While quarantine separates and restricts the movement of people who were exposedto a contagious disease to see if they become sick, isolation separates sick peoplewith a contagious disease from people who are not sick. Since all age groups areat risk of having COVID-19 infection (Coronavirus) but some may or may not end upwith it, which depends upon many factors, like transmission Rate (Ro) number of newly infected people from a single case, and whether asymptomatic transmission ispossible etc.
The attack rate or transmissibility (how rapidly the diseasespreads) of a virus is indicated by its reproductive number (Ro), represents theaverage number of people to whom a single infected person may transmit the virus.WHO estimated Ro to be between 1.4 and 2.5, while other studies have estimated aRo between 3.6 and 4.0, which means an infected person can give this disease onan average to 3 to 4 persons, which depends upon effective contact time (about 15minutes of close contact in this disease), viral load of patient at the time ofcontact and susceptibility of the contact (immunity etc.). An outbreak with a reproductivenumber of below 1 will gradually disappear. For comparison, the Ro for the commonflu is 1.3 and for SARS it was 2.0.
Coronavirus case fatality rate (percent of cases that resultin death) has been estimated at around 2% in China, which is subjected to changedepending upon the demography, health care set up, possible mutation of virus andgenetic and environmental factors of a particular population. SARS (November 2002to July 2003) was a coronavirus that originated from Beijing, China, spread to 29countries, and resulted in 8,096 infected people with 774 deaths (fatality rateof 9.6%). MERS (in 2012) killed 858 people out of the 2,494 infected (fatalityrate of 34.4%). Although COVID-19 has lower case fatality rate, its transmissionis high which can result in peak number of cases within short span of time, whichwe cannot afford because of limited health care resources. Presently we havemore than 100 confirmed cases in Valley, which may not actually represent the trueburden as about many cases have mild (with flu- like symptoms) to no symptoms, somehave severe diseases and some may need criticalcare. However, majority cases have also potential to transmit it to others, whichmay have severe disease or even need critical care. Therefore, taking all thesethings in consideration and as per mathematical model of disease transmission ofinfectious diseases, it is expected that if quarantine, isolation and other measuresare not taken seriously we may be dealing with myriad of patients within short spanof time. As the symptoms of COVID-19 may appear in as few as 2 days or as long as14 (median incubation period 5 days), during which the virus is contagious but thepatient does not display any symptom (asymptomatic transmission), we expect on anaverage 4 new patients for every patient in 5 days' time. Therefore, if forexample, we have 50 patients (10 confirmed and 40 unconfirmed in community) after 5 days there may be about 200 infected persons,after 10 days 800 plus, after 15 days 3200 plus after 20 days 12800 plus and soon. Although only 20% may land in our health setup, means we may have around 3200plus confirmed cases. This transmission chain can be broken by measures like quarantineand isolation in persons with history of exposure and home quarantine and home isolationif you have flu like symptoms due to any reason as the virus is in community now.And above all if we are able to break the chain by reducing the transmission to1 or less than one, outbreak will automatically stop as Ro will be <1 asalready explained. We recommend that people should take lockdown in full sprit to save themselves, their familyand the community. Any person with flu like symptoms and history of travel shouldreport to health authorities and take necessary precautions.