BY: Dr. Abdul Rouf
Quarantine and Isolation are public health practices to protect the 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 exposed to a contagious disease to see if they become sick, Isolation separates sick people with a contagious disease from people who are not sick. Since all age groups are at risk of having COVID-19 infection (Coronavirus) but some may or may not end up with it, which depends upon many factors, like transmission Rate (Ro) number of newly infected people from a single case, and whether asymptomatic transmission is possible etc.
The attack rate or transmissibility (how rapidly the disease spreads) of a virus is indicated by its reproductive number (Ro), represents the average 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 a Ro between 3.6 and 4.0, which means an infected person can give this disease on an average to 3 to 4 persons, which depends upon effective contact time (about 15 minutes of close contact in this disease), viral load of patient at the time of contact and susceptibility of the contact (immunity etc.). An outbreak with a reproductive number of below 1 will gradually disappear. For comparison, the Ro for the common flu is 1.3 and for SARS it was 2.0.
Coronavirus case fatality rate (percent of cases that result in death) has been estimated at around 2% in China, which is subjected to change depending upon the demography, health care set up, possible mutation of virus and genetic and environmental factors of a particular population. SARS (November 2002 to July 2003) was a coronavirus that originated from Beijing, China, spread to 29 countries, and resulted in 8,096 infected people with 774 deaths (fatality rate of 9.6%). MERS (in 2012) killed 858 people out of the 2,494 infected (fatality rate of 34.4%). Although COVID-19 has lower case fatality rate, its transmission is high which can result in peak number of cases within short span of time, which we cannot effort because of limited health care resources. Presently we have 10 confirmed cases in Valley, which may not actually represent the true burden as about 80°% of cases have mild (with flu¬like symptoms) to no symptoms, 15% have severe diseases and 5%may need critical care.
However, these 80% cases have also potential to transmit it to others, which may have severe disease or even need critical care. Therefore, taking all these things in consideration and as per mathematical model of disease transmission of infectious diseases, it is expected that if quarantine, isolation and other measures are not taken seriously we may be dealing with myriad of patients within short span of time. As the symptoms of COVID-19 may appear in as few as 2 days or as long as 14 (median incubation period 5 days), during which the virus is contagious but the patient does not display any symptom (asymptomatic transmission), we expect on an average 4 new patients for every patient in 5 days’ time. Therefore, if 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 days3200 plus after 20 days 12800 plus and so on. Although only 20% may land in our health setup, means we may have around 3200 plus confirmed cases. This transmission chain can be broken by measures like quarantine and isolation in persons with history of exposure and home quarantine and home isolation if 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 to 1 or less than one outbreak will automatically stop as Ro will be <1 as already explained. We recommend that people should take lockdown in full sprit to save their selves, their family and community. Any person with flu like symptoms and history of travel should report to health authorities and take necessary precautions.
Author is working as Demonstrator in Government Medical College Anantnag in Department of Community Medicine. He can be reached at a.rouf.dr@gmail.com
