Fourth Dose Against COVID-19. What is its Progress?

The application of the second booster dose, also known as the fourth dose, has generated controversy. Learn about the recommendations of the authorities and how their approval has progressed in the world.

COVID-19 vaccine containers and syringes

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LatinAmerican Post | María Fernanda Ramírez Ramos

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Leer en español: Cuarta dosis contra la COVID-19 ¿Cuál es su avance?

According to information from Our World in Data, 64.7% of the world population has received at least one dose of the Covid-19 vaccine. However, according to the data collected by said portal, on average in Africa only 15.37% of people have the complete initial vaccination schedule and 5.14% more at least the first dose. Meanwhile, in other places on the planet, the fourth dose has already begun to be applied, such as in the United States. In this country, at the end of March, the United States Food and Drug Administration (FDA) authorized the application of the second booster dose (fourth dose) with the Pfizer-BioNTech vaccines or Moderna for people over 50 years of age and certain immunosuppressed people, after at least four months have passed since the last vaccine. In fact, the president of the nation, Joe Biden, has already received his reinforcement.

“Current evidence suggests some decline over time in protection against serious consequences of COVID-19 in older and immunocompromised people. According to an analysis of emerging data, a second booster dose of the COVID-19 vaccine from Pfizer-BioNTech or Moderna could help increase levels of protection for these people who are at higher risk, ”said the director of the Center of FDA Biological Evaluation and Research, Peter Marks. These decisions were made based on surveillance data provided by the Israeli Ministry of Health from the application of approximately 700,000 fourth doses. In fact, Israel was the first State to apply these doses.

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Cuba and Chile, pioneers in Latin America

After Israel, Cuba and Chile have been among the first countries to begin the application of the fourth dose. In Chile, since January, people with immune system problems, older than 12 years have been able to access this dose. Also, since February, those over 55 have accessed the fourth dose. For its part, Cuba has conducted clinical studies with its vaccine, which have determined the effectiveness of the fourth dose. Since November 2021, health workers, risk groups and other population groups have received this dose, according to the country's Ministry of Public Health.

Likewise, other Latin American countries have joined the vaccination of the fourth dose. In Brazil, since the beginning of the year, there is authorization for immunosuppressed people to access reinforcement. Likewise, cities such as São Paulo began vaccination of this dose for the elderly in March. In Colombia, at the end of March, the Ministry of Health and Social Protection authorized the distribution of the fourth dose for the population group of people with organ transplants or autoimmune diseases. Likewise, since March 18, in El Salvador these second reinforcements are being applied to people over 12 years of age.

Prior to Easter, Ecuador announced that it would begin with the application of the fourth dose to people with diseases that make them vulnerable to the coronavirus and to people over 50 years of age. As for Argentina, the situation is special, since the country's health authorities do not recommend the application of the second booster, but they have enabled the possibility of it for people vaccinated with Sputnik who wish to travel and need to present one of the internationally approved vaccines.

The European Medicines Agency does not advise a fourth dose

One of the most recent announcements regarding vaccination with the fourth dose has been given by the European Center for Disease Prevention and Control (ECDC) and the COVID-19 working group of the European Medicines Agency EMA. "It is too early to consider the use of a fourth dose against COVID-19 from Pfizer and Moderna in the general population," they indicate in their statement.

"As revaccination campaigns could start in the fall, authorities will consider the best time to administer additional doses, possibly taking advantage of updated vaccines," the agencies said. Meanwhile, they insist that it is a priority to complete the initial vaccination, with two doses, for all the people who have not yet been inoculated.