Principal Secretary, Health, Sanjay Kumar said two males - aged 27 and 55 years - from Rohtas, a 35-year-old man from Kurtha in Arwal district and two females from Bhojpur and Saran district tested positive for coronavirus.
"We are ascertaining their infection trail," Kumar said.
Of the total 38 districts in the state, the outbreak has spread to 21. Arwal, which reported its first positive case, is the new entrant in the list of districts where cases of COVID-19 have been reported.
The state on Friday witnessed the biggest spike in COVID-19 cases when as many as 53 people tested positive for coronavirus, taking the total number of cases to 223 till Friday evening, less than a week after crossing the three-digit mark.
Jamalpur town in Munger reported an alarming 30 cases, while a dozen more were reported from a village in Buxar apart from Madhepura and Aurangabad registering their first cases on Friday.
Munger accounted for 62 cases while Nalanda reported 34 cases, making these the two worst affected in the state. Six patients from Munger have recovered and one has died.
The total number of active cases now stands at 176. Two patients, including one from Vaishali district, have died while 45 have recovered.
The number of samples tested so far is 16,050.
Among the other COVID-19 affected districts, Siwan reported 30, Patna 26 and Buxar 20.
Although the state, which is home to about 10 per cent of the country's population, accounts for less than one per cent of the total number of COVID-19 cases, the spike witnessed in the past one week has sparked concerns.
The state had witnessed its first couple of cases on March 22 and on April 19, it crossed the three-digit mark with the total reaching 113. The number has nearly doubled since then.
Taking serious note of the rise in cases, the state Health department has already issued a circular making it mandatory for all people to wear face masks while travelling and visiting public places like food, vegetable and dairy and medicine shops.
Those failing to do so would be penalized as per provisions of the Bihar Epidemics Diseases, COVID-19 Regulations, the department added. AR RG RT