Significant drop in ‘good’ antibodies – Dr Jeewandara
Neutralising antibodies (NAbs) also known as ‘good’ antibodies had significantly reduced in those who obtained the Oxford AstraZeneca/COVISHIELD vaccine after four months of administering the first dose, said Dr. Chandima Jeewandara, Director of Operations and Clinical Services at Allergy Immunology and Cell Biology Unit, University of Sri Jayewardenepura.
He made this remark, in reference to a recent study conducted in Sri Lanka into the Immune responses to a single dose of the vaccine in healthcare workers.
Therefore, it is necessary to obtain the second dose of the vaccine as single dose is not enough, Dr. Jeewandara pointed out and added one cannot mix and match the AstraZeneca / COVISHIELD vaccine with other vaccines like Sinopharm as there is no data to support this claim.
He said that 553 voluntary participants who had only obtained the first dose of the Oxford AstraZeneca / COVISHIELD were used in a study to determine the percentage of neutralising antibodies.
The health workers who received the vaccine show positive immunogenicity results after 28 days of administering the first dose and 93.4 per cent of them had developed antibodies against SARS-CoV-2 virus after inoculation of the COVID vaccine.
Speaking further, Dr. Jeewandara noted that this finding is alarming as the significant reduce of ‘good antibodies’ will also reduce the protection against various COVID-19 varients.
Moreover, a second study with 553 voluntary participants investigated the cell responses and it was revealed that 93 per cent of the participants had antibodies at 16 weeks after the first dose, and beyond.
However, the key finding is that the ‘good antibodies’ had decreased from four weeks to 16 weeks, by approximately 26.1 per cent.
He said in order to reach a decision on whether the delay in the second dose would require another two doses or one simple dose to generate ‘good antibodies’ the memory cells will have to be assessed.
The study found that the participants had very good T & B cell responses which can be boosted with a booster dose, he said.
When they get the second dose, there is a theoretical possibility that they will produce sufficient antibodies for protection against the different COVID-19 variants, Dr. Jeewandara noted.