How long does the protection of each vaccine last against COVID 19?

A study by Australian researchers answers one of the most common questions about vaccines: how long does the actual protection of each of the formulations developed against the coronavirus last.

The results suggest that the more protection you protect from a vaccine immediately after administration, the longer your protection will last.

The model developed by scientists Miles Davenport of the Kirby Institute at the University of New South Wales in Sydney is based on the fundamental assumption that high levels of neutralizing antibodies – which are a subset of antibodies that can inactivate the viruses – correlate with immune protection.

They used the data available on the vaccines produced by the companies. Pfizer-BioNTech, respectively from the United States and Germany; Moderna, from the United States; Sputnik-V, from Russia; Bharat Biotech, from India; Johnson & Johnson, from the United States; AstraZeneca; from England; and Coronavac from Sinovac Biotech, China.

They were able to delineate the state of the levels of neutralizing antibodies generated by each of the vaccines over 250 days.

In addition, research highlights the use of convalescent plasma as a means of containing the SARS-CoV-2 coronavirus pandemic, which has obtained emergency use clearance from the United States Food and Drug Administration. in February 2021. patients as part of the agency’s ongoing efforts to fight COVID-19.

Australian researchers compared these trajectories to those of recovered COVID-19 patients they had natural immunity. Additionally, they modeled how lower antibody levels might behave against newer variants of the coronavirus. They also used convalescent sera as a benchmark to standardize vaccine data, which in their original state came from a diverse set of tests and therefore were difficult to collect.

Another result that the work contributed is that there would be differences in the levels of neutralizing antibodies depending on the vaccine applied.

Vaccines Pfizer and Moderna were the most effective, with an initial efficacy of 95% which did not drop to 50% until around day 200. The Sputnik V vaccine maintained an efficacy of 70% after 150 days and 50% after 125 days.

Meanwhile, the Johnson & Johnson and AstraZeneca had an initial efficacy of 67 and 62% respectively, but they hit the 50% protection mark around day 50.

At the opposite extreme was Sinovac’s Coronavac vaccine, which is given in Chile, among other countries. This vaccine had an initial efficacy of 50 percent, but they found protection after two or six months of administration according to the modeling.

However, the results do not mean that some of the licensed vaccines should be excluded. They admit that the study is predictive, not prescriptive, and that it is based on hypothetical means drawn from available data on convalescent sera.