Several hospitals in the city said most of the Covid patients who have turned critical or died had not taken the precaution or booster vaccine dose.
The state health department is also conducting a study to find out how many people who have died during the current surge had not taken the precaution dose.
On Friday, West Bengal recorded 3,067 new Covid cases and five deaths. According to the state health department, 737 Covid patients were admitted in hospitals.
“Of those admitted in hospitals, around 120 are requiring oxygen support and a little more than 10 are on ventilation support. Our assessment is that the disease is less severe compared with the third wave but a few patients are turning critical,” a senior official of the state health department said.
“The percentage of critical patients seems to be more this time compared with the third wave. So, people should be more careful, especially those who are elderly or those who have comorbidities,” he said.
The official said booster or precaution dose would reduce chances of severe disease.
“Also, it will build confidence among people. We are conducting a study to find out how many people who have died in the fourth wave did not take the third dose,” the official said.
Doctors and health experts have said there is evidence that the precaution dose is reducing chances of severe disease in people infected with the Omicron variant of the coronavirus or its sub-variants.
The Telegraph reported on Friday that Priya Abraham, director of the National Institute of Virology, Pune, said studies had shown that antibodies start declining four to six months after taking Covid vaccines.
The booster or precaution dose, she said, increases the antibody levels.
Several private hospitals in Kolkata said most critical Covid patients had not taken three doses.
Twenty patients were admitted at the RN Tagore International Institute of Cardiac Sciences on Friday, of whom four had taken the precaution dose, said officials.
“There are four critical patients, who have comorbidities. Among them three have not taken three doses of vaccine,” said R. Venkatesh, regional director, east and south, Narayana Health, which runs the RN Tagore hospital.
At Charnock Hospital, 13 Covid patients were in the ICU on Friday, of whom only five had taken precaution doses. Two of the patients have not taken any vaccine dose, said Ipsita Kundu, CEO of Charnock Hospital.
“We have observed during the recent surge that those who got admitted with all three doses are having moderate symptoms and most of them are not requiring oxygen support. But those with comorbidities and who have not taken the precaution doses are turning critical,” said Pradip Tondon, CEO of Belle Vue.