LISBON, March 1 (Xinhua) -- The Portuguese health authorities decided on Monday to increase the dosing interval of Pfizer's COVID-19 vaccine from 21 to 28 days.
"We have to fine-tune our plan, making adjustments to reality, depending on the vaccine arrival schedule and the calendar changes," Assistant Secretary of State for Health Antonio Lacerda Sales told journalists.
With this change, he said, it will be possible to meet the country's goal of vaccinating another 100,000 people by the end of March.
To date, about 35 percent of the population aged 80 and over and 70 percent of Portugal's health care professionals have already received the first dose of the vaccine.
Portugal closed the month of February with 868,951 vaccines administered, of which 603,585 are the first dose, according to official data.
As the world is struggling to contain the pandemic, vaccination is underway in some countries with the already-authorized coronavirus vaccines.
Meanwhile, 256 candidate vaccines are still being developed worldwide -- 74 of them in clinical trials -- in countries including Germany, China, Russia, Britain, and the United States, according to information released by the World Health Organization on Feb. 26.