By Sneha Mordani: New Delhi: Covid cases rising in India, courtesy of XXB.1.16, a subtype of Omicron, the fifth variant of concern. Daily cases surpassed 3,000 for two days in a row. On Saturday, India reported nearly 3,000 cases and the positivity rate approached nearly 3 again.
Amid the rise in cases and XXB.1.16’s call to escape immunity from vaccines and also from natural infections, we asked experts if the current vaccines that Indians have been taking along with the third dose would offer any protection.
“PROTECTION AGAINST SERIOUS DISEASE WILL NOT DECREASE OVER TIME”
“India has high vaccination coverage against Covid and several vulnerable people have also taken booster doses. In addition, a high percentage of people have acquired immunity after surviving natural infection. When we talk about immunity, there are two functional categories, protection against viral infection and protection against serious consequences in case of infection,” said Dr. Rajeev Jayadevan, co-chair of the Kerala Covid Task Force.
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He added that vaccines would not protect against infection. “Therefore, a minimum level of precautionary measures are required, which need to be improved in times of surge,” he said.
Protection against serious illnesses does not diminish over time, he said. “That’s because immune memory, with specialized cells that live in both tissues and our bone marrow, provides a long-term response to infection if and when it occurs, preventing serious organ damage. This immune memory protects us even when our circulating antibody levels drop over time,” he said.
He explained that this applies to all Omicron sub-lineages. “It’s unclear how that immunity will hold if an entirely new variant arrives.”
The doctors also stressed the need to take the third booster dose.
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“Vaccination remains our only armor to be safe from the serious consequences of the virus. Full vaccination along with booster vaccination has helped prevent serious lung disease and cases of pneumonia and reduced the need for hospitalization during such Covid waves. The booster or preventive dose was made available almost a year ago and most people have not yet received it,” said Dr. Sharwari Dabhade Dua, Specialist and Endocrinologist at Rosewalk Hospital.
NO FOURTH DOSING REQUIRED
Experts also explained why a fourth dose would serve no purpose. Experts said the vaccines used in India were developed three years ago using the strain of the Wuhan wild virus strain. The vaccines may not be as effective now against the new generation of variants, particularly the Omicron variant, which has over 1,100 sub-sub lineages, and therefore a fourth dose is not required.
Protection against serious illnesses is guaranteed from three previously taken doses, it said.
“The Indian population is well positioned with two doses of primary immunization and a booster shot. There is currently no data showing that a fourth dose is required. Also, for those on the booster dose now, it is advisable to look at the intranasal vaccine, which offers excellent IGA and resident memory T-cell immunity for long-term lung protection.” Sanjeev Bagai, chairman of the Nephron Clinic, told India Today.
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DIVUAL VACCINES THE WAY AHEAD?
Experts said that next-generation vaccines will best help our situation. The bivalent coronavirus vaccines contain a component of the original virus strain to offer broad protection against Covid and a component of the Omicron variant to offer better protection. “Bivalent Vax (still available in India) is superior to monovalent,” said Dr. Bagai, adding that a fourth dose after the last 2+1 boost isn’t worth much.
He advised the use of the intranasal vaccine for those considering the third dose until bivalent vaccines are developed or made available in India.
“The intranasal Vax is also available and has shown excellent lung protection with rTmcells at the entry site and sIgA local mucosal protection. That means it offers better immunity to long-term memory,” he said.