Proper implementation of a zonal lockdown difficult without ramping up testing, antibody tests, to identify asymptomatic patients
Welcoming the government decision to conduct zonal lockdowns, experts are saying proper implementation of the system can help reduce transmission of Covid-19 and also allow normal life to resume to some extent.
However, zonal lockdowns are unlikely to be effective without a significant increase in testing to get an accurate picture of the Covid-19 situation on an area by area basis. Allowing free movement and public transport before zones are properly determined poses a major threat to public health, they added.
BSMMU public health department Associate Professor Atiqul Haque told Dhaka Tribune, the goal is to bring the transmission rate (Ro) of the virus down from 2.6 to less than 1.
“A zonal lockdown can be fruitful, but there are problems with zoning and mapping. We don’t have any real time data on how many people have been infected. We are testing for symptomatic cases, but how can we determine if there are asymptomatic cases roaming around?” he said.
He suggested the authorities conduct a mass survey with antibody tests on samples randomly collected from every district, in order to identify asymptomatic Covid-19 patients who may have unwittingly spread the novel coronavirus.
“Such large scale testing can help map the zones properly, but it will take some time,” he added.
Spain and the state of Indiana in the US are examples of places where mass antibody tests were conducted to estimate the dynamics and rate of spread of coronavirus.
NIPSOM Professor Be-Nazir Ahmed also said antibody tests are critical to estimate and understand the dynamics and rate of the virus’ spread.
“But as it might take time, we can use the data available at the IEDCR to map primary zones. We cannot afford to have our green zones turned into yellow or red. After mapping primary zones, the DGHS can conduct nationwide zoning,” he said.
“The authorities need to trace, test, and isolate every possible case before setting up zones,” he added.
The infectious disease expert also said community health care providers (CHCPs) are closer to rural people and will be crucial to finding out if anybody has any symptoms. They can help isolate and ensure primary treatment for patients, and make reference calls as well.
Once people are motivated through access to better services, they will not hide symptoms from health service providers and help turn yellow zones into green, and red to yellow.
“Zones should have been set up before lifting the lockdown. Now, we have to implement it right,” he added.
It remains unclear who at the Health Ministry will map the zones and under what criteria.
Contacted about zoning and mapping by DGHS, adviser and former IEDCR chief scientific officer Mushtaq Hossain said the Communicable Disease Control (CDC) of DGHS will map the zones and IEDCR will provide technical support.
Meanwhile, Director (Disease Control) and Line Director (CDC) Dr Shahnila Ferdousi said on Thursday that they were yet to receive any directives on mapping zones. A CDC source also said they are yet to receive any such directives.
However, a ministry source said the government is likely to start implementing zonal lockdowns from this week.
According to the government plan, hotspots with the highest number of cases will be marked as red zones, areas with a small number of cases will be termed yellow zones, and green zones will be areas with zero confirmed cases in the last 21 days.
If there are over 40 Covid-19 patients for 100,000 people, the area will be classed a red zone, sources said.
Most areas in Dhaka north and south city corporations, and the Chittagong, Naryanganj, and Gazipur city corporations, are likely to be red zones as the infection rate was highest in these four cities.