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Study: Delaying the second dose of the Corona vaccine may improve the effectiveness of vaccine programs

A study published in PLOS Biology confirmed that prioritizing widespread vaccination with the first available doses may reduce new infections and deaths.

Two of the Corona vaccines currently approved in the United States require two doses, Pfizer and Moderina, which are taken from three to four weeks, however, there is little data indicating the best ways to reduce new infections and hospitalization, while researchers from York University in Toronto, Canada, and colleagues indicated Until delaying the second dose can improve the effectiveness of the vaccine programs.

The emergence of new and more contagious variants of Corona has led to a public health debate about whether more individuals should be vaccinated with the first dose of available vaccines and delay the second dose, or prioritize completing the two-dose series on a basis according to schedules tested in clinical trials.

In order to compare the epidemiological impact of each vaccination strategy, the researchers built a mathematical model that simulated the transmission of the Corona virus and different vaccination schedules with the second late dose, and the model simulated several scenarios, including a range of pre-existing immunity levels in the population and reduced the effectiveness of the vaccine for the first dose when followed with an interval Longer interval between doses.

The authors found that delaying the second dose by 9-15 weeks after the first dose avoided further hospitalization, infections, and deaths compared to following the recommended schedules for the Moderna and Pfizer vaccines.

The authors said: "Our results show that prioritizing vaccine coverage with rapid distribution of the first dose will be critical to mitigate negative outcomes and allow the healthcare system to also address medical needs."