Nov, 2021 - By WMR
Researchers found that half-dose of Covid-19 vaccine for first dose protects people more potentially than two standard doses.
A mistake in dosing of AstraZeneca’s COVID-19 vaccine trial revealed the efficiency of the vaccine, however, it also led to an unexpected discovery where it was found that people who mistakenly received half dose of the vaccine as their first dose were protected more potentially against COVID-19 than people who were administered two standard dose. In order confirm the findings, a team of scientists from Northwestern University replicated the findings and found that some vaccine could have more potential if administered in lower first dose than the second.
The team experimented the effects of the COVID-19 vaccine prime dose in mice. It was found that the first shot of lower dose followed by a full-dose booster shot, substantially improved the efficiency of a COVID-19 vaccine. The booster dose creates more T-cells and antibodies in the mice, which allows these cells to develop a much more vigorous responses of immune system against the virus. A method termed as dose escalation is used in clinical trials of vaccine, where one person is administered with lower dose and same amount of booster dose and another person is administered with higher dose and same amount of booster dose. In the vaccine trial of AstraZeneca, subjects who received full dose as first shot were given the booster dose after 3-4 weeks and subject who received lower first dose had longer prime-boost interval. The scientists imitated this procedure in mice and it also reported that the longer prime-boost interval enhances the response of immune system.
There is not much research on this subject that is conducted on humans, therefore, the scientists cannot directly extrapolate these findings to humans. However, the error in the AstraZeneca vaccine trial gives convincing evidence of induced optimal response due to a lower first dose and a longer prime-boost interval than standard method.