The health department has set up a medical board to look into the possible causes of illness of a nurse of the BC Memorial Hospital for Children who had to be admitted to NRS hospital on Saturday after receiving a jab of Covishield.

The woman, in her 40s, complained of numbness in her hands and feet following the inoculation.

A health worker in Howrah’s Bagnan, too, complained of similar adverse effects after the vaccination and is under observation at Bagnan Rural Hospital.

Officials of the state health department said the condition of both women are stable.

A dozen of others across Bengal who had complained of uneasiness as an after-event of immunisation (AEFI) on Saturday were sent home after being observed for some time, senior health department officials said. Almost all of them complained of dizziness.

Their blood pressure and other parameters were continuously monitored by doctors who were deployed by the health department to treat such patients across all vaccination sites, said officials.

Doctors said the woman admitted to the NRS Medical College and Hospital was on medication for bronchial asthma from childhood.

“She is under observation and a team of critical care experts and others is trying to ascertain whether her numbness was related to the Covishield shot,” an official at Swasthya Bhavan said.

“She has undergone several tests. The potassium level in her blood dropped. That can cause muscular weakness. Doctors are trying to find out whether the fall in the potassium level was an after-effect of immunisation.”

Chief minister Mamata Banerjee had on Friday requested all recipients to alert the state health department if someone developed any complications after getting the shot. “Amra dekhey nebo (We will look into it),” she had said.

Senior doctors who are part of the AEFI team in Calcutta — such teams have been formed for all districts — said that only 14 of the 15,707 recipients of the vaccine on the first day across the state had complained of after-effects. “That’s hardly a cause of concern as the number is less than 0.5 per cent of the recipients on the first day. No one complained of severe illness,” said a member of the team who refused to be named.

On Sunday, the health department decided that starting next week, the vaccination drive would be carried out four days a week — Mon-day, Tuesday, Friday and Saturday.