Covid-19: Second dose of Pfizer’s vaccine triggers massive immune response, study shows

A recent study by the Stanford University School of Medicine has found that Covid-19 vaccine’s second dose provides broad antiviral protection by inducing a powerful boost to a part of the immune system. Stanford Medicine said in a press statement that the finding strongly corroborated the view that the second jab should not be missed. The study, which was published in Nature, looked at the immune responses to the Pfizer-BioNTech vaccine. Stanford Medicine had started administering the company’s shots in December 2020.

Analysing blood samples of individuals who had been given the shot, the researchers measured levels of immune-signalling proteins, counted antibodies, and also characterised the expression of every gene in the 242,479 separate immune cells’ type and status genome.

Professor Bali Pulendran of Stanford Medicine, who was among the senior authors of the study, assessed the activity among all immune cell types influenced by the vaccine, including their activation levels, numbers, the proteins and metabolites they manufacture and secrete upon inoculation, and the genes they express.

Fifty-six healthy volunteers were selected for the research. The team drew their blood samples at several time points before and after the first and second vaccine jabs. The first shot increased SARS-CoV-2-specific antibody levels, the researchers found. However, this was nowhere near as much as the second shot, which also does things the first shot doesn’t do, or barely does.

Pulendran said in the statement that there were powerful beneficial effects of the second shot that far outweighed those of the first jab. He added that the second shot stimulated a multiple fold rise in antibody levels, terrific T-cell response, which was absent after the first shot, and enhanced innate immune response.

A group of first-responder cells that have been newly discovered are also mobilised by the vaccine, especially after the second dose. An actual Covid-19 infection barely budged these cells, identified first during a recent study of vaccines, led by Pulendran. However, the vaccine manufactured by Pfizer-BioNTech was found to have induced them.