United States President Joe Biden and First Lady Jill Biden on Monday received booster shots of the Covid-19 vaccine.

The country had on Friday begun rolling out booster shots of the Pfizer-BioNTech booster vaccine for its vulnerable population, including senior citizens and those who work in high-risk environments.

The US president, who is 78-years-old, was eligible for the booster dose as he was inoculated with the second one over six months ago, CNN reported.

Biden said that booster shots were important but the most important task was to inoculate more people, according to the news channel.

The president urged unvaccinated citizens to get themselves inoculated on priority. “This is a pandemic of the unvaccinated,” he said, according to CNN. “That’s why I’m moving forward with vaccination requirements wherever I can.”

Biden said that more than 77% of the adults in the US had received at least one vaccine dose. “About 23% haven’t gotten any shots, and that distinct minority is causing an awful lot of us an awful lot of damage for the rest of the country,” he added.

The rollout of booster shots has become a subject of international debate with the World Health Organization repeatedly highlighting unequal access to vaccines.

On September 8, WHO chief Tedros Adhanon Ghebreyesus had called for a moratorium on administering booster shots till at least the end of the year to allow every country to vaccinate at least 40% of its population.

The coronavirus has infected over 23.23 crore people in the world and caused more than 47.56 lakh deaths since the pandemic broke out in December 2019, according to Johns Hopkins University.

The United States has recorded 4,31,16,407 coronavirus cases and 6,90,426 deaths so far.