Pfizer and BioNTech said on Monday that their anti-COVID-19 vaccine was 100% effective four months after the second dose in children aged 12 to 15. The companies said that in the new data, 2,228 people were involved in the trial. The use of anti-Covid vaccines started worldwide since November last year. According to the data of John Hopkins University, 7 billion 44 crore 82 lakh 49 thousand 016 doses have been given worldwide so far. ,