Bangladesh on Friday recorded a Covid-19 test positivity rate of less than 10% for the fourth consecutive day, the longest stretch of single-digit test positivity in the country since the government expanded testing facilities in early April.
Although the reduced test positivity rate is a sign of hope, experts warn that it could rise again if people stopped following health guidelines.
They also said the data might be misleading, as the reduced test positivity rate might be the result of the unwillingness of some people to get tested or reduced testing during the recent holidays.
According to data provided by the integrated control room under the Directorate General of Health Services (DGHS), the daily Covid-19 test positivity rate was recorded at 9.19% on Friday, 8.6% on Thursday, 9.59% on Wednesday and 9.85% on Tuesday.
The last stretch of single-digit test positivity in the country ended on April 6, just before the government finished setting up testing facilities at the divisional level.
The test positivity rate is expected to be lower during holidays, as fewer people go for tests on holidays. However, the test positivity rates during the three-day Eid-ul-Fitr holidays were recorded at 17.2%, 20.9% and 21.56%, and during the Eid-ul-Azha holidays they were recorded at 21.98%, 24.98% and 24.05%.
Single digit test positivity rates were also recorded on May 20 and October 24, but they were not part of prolonged stretch of single-digit test positivity.
Bangladesh registered 25 deaths from Covid-19 in the 24 hours to Friday morning. With the latest development, the total number of deaths reached 7,217 in the country.
The country also logged a total of 498,293 coronavirus cases, with 1,318 people testing positive over the same period. As many as 14,336 samples, including pending ones, were tested at 159 authorized labs in the 24 hours.
Although the daily test positivity rate was recorded at 9.19%, the overall infection rate of the country stands at 16.34%.
Dip in test positivity rate not conclusive
Bangabandhu Sheikh Mujib Medical University (BSMMU) department of public health and informatics Associate Professor Dr Atiqul Haque said a small sample of data, like data for just four days, should not be used to draw conclusions.
“If the positivity rate remains low for some 10 to 14 days, at least it could be said that the country is in a reduction state. We saw a trend of increase that was higher than anticipated in the days before the dip,” he added.
If the reduction state became static, wearing masks would be the most effective way to combat transmission, the associate professor said.
However, eminent virologist Dr Nazrul Islam has a different hypothesis.
The former vice chancellor and head of the department of virology of BSMMU said: “The nature of the virus could, to some extent, lead to a hypothesis that the rate would be reduced during winter. Viral population interference might have caused the lower infection rate.”
The prevalence of at least four respiratory viruses in Bangladesh may have led the population into developing resistance against respiratory infections like Covid-19, he explained.
“If a person is already infected with a respiratory infection other than Covid-19, the virus that is already present may not allow the new virus [Covid-19] to enter the cell to get a favourable environment for reproduction,” he added.
In a recent survey, the researcher found that only 5.8% slum people who responded had antigen test confirmation, while 74% of respondents were found to have developed antibodies.
“This could be evidence of viral population interference or subclinical infection. It is still a hypothesis and not conclusive. If proved, it would be good for the country, for sure,” Dr Nazrul said.
