Scientists, health officials in dark

Health officials in the country are making predictions about the coronavirus outbreak based mostly on assumptions, not scientific analyses, experts said.

Scientists and public health experts are still in the dark, because the R-naught, which is a representation of the number of new infections estimated to result from a single case, has not been measured in the country yet.

So, it is difficult to tell at what stage the outbreak is now and when it may peak and how lethal it might get, they said.

R-naught, also called R0, gives insightful information that helps policymakers decide when to enforce strict lockdowns and when to lift the restrictions, Prof Be-Nazir Ahmed, former director of disease control at the Directorate General of Health Services, told The Daily Star.

"The government and health officials are predicting based on assumptions, not sufficient and authentic scientific evidence," he said.

"Our health officials' predictions are based on assumptions, not proper scientific data," he said.

Lower R-naught score means fewer new cases and higher score means the opposite, he added.

"So, R-naught is very crucial in understanding the current status and to predict the future and to take actions based on evidence," he added.

Experts said IEDCR was supposed to work out a plan to determine the R0 after the first case was recorded in the country on March 8.

Contacted, health officials said they started working on it, but had stumbled due to lack of available information.

IEDCR consultant and epidemiologist Mushtuq Husain said, "We are collecting data and the work is progressing."

He added that the government officials' predictions were based on analyses of daily new cases, number of tests, and mortality rate.

"But yes. R naught gives a very good direction in when to do what. The work is going on and we are hopeful of getting results soon," he said.

Experts say R-naught meant the number of new infections estimated to result from a single case. If R0 is 2.5, then one infected person might infect, on average, 2.5 others. The 2.5 others may infect another set of people at the same rate.

An R0 below 1 suggests that there are fewer new cases and that the restrictions can be lifted. An R0 above 1 suggests that the number of cases is growing and that more restrictions should be in order.

According to reports, Italy recently found out that its social and economic restrictions had pushed the virus's R0 down to 0.8. France estimated that timely lockdowns pushed RO down to 0.5 from 3.3. And India estimates its R0 to have declined to 1.36 from 1.55.

Prof Iqbal Arslan, a member of the national technical committee on covid-19, said it is always wise to follow the global practice, because of their wide range of experiments.

"But in some cases, countries can customise the global practices. If we don't follow the global practice, then certainly it will create problems," he said regarding R naught.