The National Basketball Association (NBA) has recommended its players, coaches and referees on Sunday to receive booster shots against the coronavirus, with particular urgency for those who received the single-dose Johnson & Johnson vaccine.

Working jointly based on guidance from the NBA’s public health and infectious disease experts, the league and the National Basketball Players Association said those who received Johnson & Johnson shots more than two months ago should get a booster.

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Those who had the Pfizer and Moderna vaccines at least six months ago were also advised to get a booster shot.

Those who had Johnson & Johnson vaccinations should seek a Pfizer or Moderna booster, the league’s instructed, according to Associated Press reports. Those that received Pfizer or Moderna can choose any booster that is accessible, according to the league.

Antibody levels for Pfizer and Moderna recipients fade after six months, whereas antibody levels for Johnson & Johnson recipients drop after two months, according to data analysed by the league.

Some teams already have been planning for players to receive booster shots when available. A small number of previously vaccinated NBA players have tested positive this season for COVID-19 and entered the league’s health and safety protocols.

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Those who have been vaccinated but have chosen not to acquire a booster may be subjected to game-day testing beginning Dec. 1, according to the NBA. When a person was first vaccinated and what sort of vaccination they received, the date of December 1 changes.

When the season began last month, it was estimated that 97 percent of NBA players had been vaccinated. Nearly 60% of the population in the United States — more than 193 million people — is completely immunised. More than 21 million people have gotten a booster shot, and the number is growing every day.

With inputs from the Associated Press