Civil Surgeon Dr AKM Anwarur Rauf said test reports of an office assistant, a female programme organiser and another staff member came through from Mymensingh Medical College Hospital on Monday, that confirmed their infections.
Earlier, another assistant of the same office also tested positive for the virus, Dr Anwar said.
So far, a total of 20 people were found infected by COVID-19 in Sherpur, but five of them have completed recoveries and returned home, the CS also said.
The death toll and case load caused by the coronavirus is now rising at an exponential, or logarithmic, rate in Bangladesh with 10 more people reported dead from the infection in the 24-hr period upto the briefing by DGHS on Monday, taking the death toll in the country to 101.
Besides, a record number of cases, 492, tested positive for the virus during the period, taking the number of infected cases in the country to 2948.