From the closing weeks of 2020 through February 1, 2022, more than sixty percent of the world’s population was injected with Covid-19 vaccines.
This means that in a period of fewer than fourteen months more than 4.7 billion people received at least one Covid shot. Tens of millions received as many as four doses.
The first clinical trial of Covid vaccines was launched in Germany on April 23, 2020, with the Pfizer–BioNTech vaccine. The first country to authorize the use of the vaccine in the general population was the United Kingdom. The UK issued its authorization on December 2, 2020, and this move was quickly followed by dozens of other nations. The United States issued its emergency use authorization on December 11.
This means that the massive global vaccination campaign – which quickly reached a frenzied pitch – was launched less than 8 months from the start of the clinical trials.
To begin administering a vaccine to the general population within such a short trial period was wholly unprecedented in the annals of modern medicine.
To establish that a vaccine is safe, extensive long-term testing must be carried out. This process involves multi-phase clinical trials and observational studies which include large numbers of subjects over time periods measured in years. This thorough and involved process takes at least five years to complete and is usually much longer.