Coronavirus Pfizer’s coronary vaccines have not yet provided the necessary protection for 2-4 year olds in pending trials.

Coronavirus vaccines developing company Pfizer has reported preliminary test results vaccine for children under five years of age.

According to the company, the experiments showed that two doses of Pfizer and Biontech vaccines designed for children did not produce the expected immune response in children aged 2 to 4 years. However, protection was given to children whose age ranged from half a year to two.

Preliminary results from studies in progress mean that the possible completion of the vaccine in young children will be delayed. Pfizer says it will next change the trials so that in the age group from six months to 5-year-olds, the coronary program for children also includes a third dose.

Pfizer according to the US Medicines Agency (FDA) and the European Medicines Agency (EMA) have approved the addition of a third dose to the trials.

If the third dose produces the desired results, Pfizer and Biontech estimate that they will apply for an emergency license for other coronavirus vaccines in the first half of 2022.

The studies involved 4,500 children, ranging in age from half to 12 years. According to Pfizer, in addition to American children, Finnish, Polish and Spanish children, among others, have been involved.

Vaccine efficacy has been studied in three different age groups. The youngest age group included children who were at least six months old but less than two years old. The following included those over 2 years of age but under 5 years of age.

The third age group was 5 to 12 years old, who received two doses of 10 milligrams of the vaccine. Children under 5 years of age received a twice lower dose of three milligrams. Two low doses appeared to be effective protection in children less than 2 years of age but not more than 2 years of age.

Approved by the European Medicines Agency in November for Pfizer and Biontech coronavirus vaccine for 5-11 year olds.