With the number of Covid-positive cases going up sharply, some State governments have called for reducing the gap between the second dose and precaution (booster) dose to six months from nine months.

The Andhra Pradesh and Telangana governments have asked the Union government to make it easier for people to get the booster dose early and reduce the number of serious cases and resultant hospitalisation.

Incidentally, a study conducted by the Asian Institute of Gastroenterology (AIG), has found that at least 30 per cent of the people had lost immunity six months after receiving the second dose. The study was conducted on a pool of 1,636 healthcare workers who were fully vaccinated.

People over 40 years with comorbidities such as hypertension and diabetes are vulnerable and will require a booster dose after six months of taking the second dose, the study recommended.

Andhra Pradesh, which reported a positivity rate of 25 per cent on Wednesday with over 10,000 cases, felt that reducing the time lag will help more people get the booster dose and protect themselves against the infection.

Echoing AP’s views, the Telangana government, too, favoured relaxing the criterion. It even wanted the Union government to reduce the lag to three months for health care workers, considering the fact a large number of doctors, nurses and technicians are getting infected in large numbers in the third wave.

“The government should give a booster dose to all the people above 60 years of age, including those without comorbidities,” he said in a letter to Union Health Minister Mansukh Mandaviya.

Covid antibodies

The AIG study found that about 70 per cent of the population that are vaccinated, particularly the younger population, are able to retain Covid antibodies till nine months after getting the second dose of vaccine.

The remaining 30 per cent, particularly those 40 years and above with co-morbidities, do not retain enough antibodies to tackle the infection.

“They may be at a higher risk of SARS-CoV-2 infection and these individuals should be prioritised for a booster dose after six months,” said D Nageshwar Reddy, Chairman of AIG Hospitals.

This has lent credence to the argument that the gap between the second dose and booster days should be reduced to six months.

“We are seeing a surge of infection across the country. Fortunately, the severity of the disease is mild because of multiple factors including the effect of vaccination, the intrinsic character of the variant itself, and natural immunity amongst the population,” he said.

“We found that almost 30 per cent individuals had antibody levels below protective immunity level of 100 AU/ml (arbitrary units per milliliter) after six months,” he said.

“These individuals were majorly above 40 years with co-morbidities. Of the total sample size, six per cent did not develop any immune protection at all,” he said.

The results indicate immunity levels wane with age. Younger people have more sustained antibody levels than the elderly population. “At present, the 9-month gap for prevention dose benefits 70 per cent of the population who can retain enough antibody levels beyond six months,” Reddy felt.

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