Rockland-based Pfizer says it has started testing its COVID-19 vaccine on kids as young as 2 years old.

According to Pfizer, children younger than 6 months may be evaluated once an acceptable safety profile has been established.

Pfizer believes the data for trials will likely be available in the second half of this year.

If it's proven to be safe and effective, it hopes to receive authorization to vaccinate by early next year.

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More than 4,600 kids between 6 months and 11 years old are participating in these trials in the US and Europe.

Researchers at Stanford Medicine and Cincinnati Childrens Hospital confirm their trials on ages 2 to 5 started Wednesday.

According to Pfizer, once an acceptable safety profile is established, children even younger than 6 months may be evaluated as well.

Doctors hope once the vaccine is authorized for use. parents are willing to vaccinate their children. They say vaccinating kids are vital to achieving herd immunity.

Pfizer reports that children 15 and under make up 26% of the world's population to achieve herd immunity experts estimate 80-90% of the population needs to achieve immunity through vaccinations or infections.