Lockdown logic and science behind it
The main objective of any lockdown or social distancing mechanism is a reduction in the rate of infection
NEWDELHI: As India goes under a lockdown with new coronavirus cases becoming a steady stream, it’s important to assess the role that lockdowns and strict social distancing can play in controlling the outbreak.
The objective of any lockdown or social distancing mechanism is the reduction in the rate of infection. Health experts say that social distancing is the best way to prevent hundreds of thousands of cases appearing in batches, overwhelming a country’s health care system.
When unchecked, the overwhelming nature of Covid-19 was seen in the initial outbreak of the disease in China’s Hubei province through January and February, in Italy through the end of February and early March, and New York state most recently. In all three cases, governments eventually resorted to lockdowns with varied levels of success.
What is the science behind lockdowns? very abrupt rise of cases as seen in both China and the US before any lockdowns were placed.
Given an estimated R0 of 2.4, researchers at Imperial College London predicted 81% of the population would be infected over the course of the epidemic. The biggest issue was that most of these cases occurred at the same time, causing a spike in the epidemic curve, overburdening health care systems.
2: LOCATION-WISE LOCKDOWN In
this case, a region with a high number of cases is locked down -as in China’s Hubei .
In a study titled ‘The effect of travel restrictions on the spread of the 2019 novel coronavirus (COVID-19) outbreak’ published in the journal Science by a group of American, Italian and Chinese researchers on March 6, scientists found that travel restrictions in Wuhan slowed the spread. While the model output showed no noticeable differences in the epidemic in Wuhan, it showed a delay of about three days for other locations in China.
This strategy focuses on slowing down, not necessarily suppressing the epidemic. This flattens the curve slightly, buying time to strengthen health care facilities. It also means a reduction in peak health care demand, freeing up hospital beds and protecting those most at risk.
3 : LOCKDOWN AND HOME-QUARANTINE
In this case, extensive social distancing is applied throughout the populace by limiting people’s movement through both homequarantines and lockdowns over a period of time.
The aim is to reduce R0, to below 1 and take case numbers to low levels or eliminate humanto-human transmission.
In the Imperial College model, this required social distancing for the entire population, over a long period of time.
“It is likely such measures will need to be in place for many months, perhaps until a vaccine becomes available,” one of the study’s researchers, Neil Ferguson, said in a written statement issued by the college. “The effects on countries and the world will be profound.”
This strategy yields the best results so far as the virus spread ends up being a trickle.
By closely monitoring rise in the infections, governments may be able to lift curbs temporarily, and reinstate them if numbers began to rise.
This is the kind of lockdown India has enforced for three weeks.
In this case each dot is a person who is free to move around and interact with other people. Based on R0= 2.4, we can assume that each infected person will infect 2 to 3 people on average
In this case a region that has a high number of cases is locked down entirely. This is what was done in China’s Hubei province and Italy’s Lombardy, in an attempt to contain the infection to that particular region
In this phase, once an outbreak flares in a region, we create a brief lockdown over a city or region to contain the spread of the disease there. This generally leads to a high concentration of cases in the area, but contains the virus there
In this scenario extensive social distancing is applied throughout the populace by limiting people’s movement through both home-based quarantines and lockdowns