A healthcare worker prepares a vaccination for Pfizer coronavirus disease (COVID-19) in Los Angeles, California on January 7, 2021.

Lucy Nicholson | Reuters

Pfizer announced that it has started a clinical trial testing the Covid-19 vaccine in healthy children aged 6 months to 11 years. This is a critical step in gaining regulatory approval to vaccinate young children and fight the pandemic.

The first participants in the study have already made their recordings, which were developed in collaboration with the German drug manufacturer BioNTech, New York-based Pfizer announced on Thursday. It is intended to enroll 144 children.

In the first phase of the study, the company will determine the preferred dosage level for three age groups – between 6 months and 2 years, between 2 and 5 years and between 5 and 11 years. The children will first receive a dose of 10 micrograms of the vaccine before gradually moving on to higher doses, Pfizer said. Participants also have the option of ingesting 3 micrograms doses. The adult Covid vaccine requires two shots that contain 30 micrograms per dose.

Researchers will then evaluate the safety and effectiveness of the selected dose levels in the next phase of the study, with participants being randomly selected to receive the vaccine or a placebo, the company said. After a 6-month follow-up visit, children who received a placebo will have the option of receiving the vaccine, it said.

“Pfizer has extensive experience developing clinical trials of vaccines in children and infants and is committed to improving the health and well-being of children through well-designed clinical trials,” the company said in a statement.

Pfizer’s vaccine has already been approved for use in the United States by Americans 16 and older. Clinical studies testing the vaccine in children whose immune systems may react differently than adults are still to be completed.

Vaccinating children is critical to ending the pandemic, say public health officials and infectious disease experts. The US is unlikely to achieve herd immunity – or if enough people in a given community have antibodies to a given disease – before children can be vaccinated. According to the government, children make up around 20% of the US population.

In late January, Pfizer announced that it had fully registered the Covid-19 vaccine study for children ages 12-15. The company announced Thursday that the data in this cohort was “encouraged” and hopes to provide more details about the study. soon.”

Moderna, which also has a US-approved vaccine, announced on March 16 that it has started testing its shot in children under the age of 12. Moderna started a study in December testing children aged 12 to 17 years.

Johnson & Johnson plans to test its single-shot vaccine in infants and even newborns after it was first tested in older children, according to the New York Times.

The Chief Medical Officer of the White House, Dr. Anthony Fauci, speaking to a House committee earlier this month, said the US could start vaccinating older children against Covid-19 from this fall, while elementary school children may start vaccinating early next year.

Pfizer’s announcement comes two days after the start of an early-stage clinical trial of an experimental oral antiviral drug that could be used at the first sign of Covid infection.

Health experts say the world will still need a slew of drugs and vaccines to end the pandemic that has infected more than 30 million Americans and killed at least 545,282 people in just over a year, according to Johns Hopkins University.