US health consultants suggested on Thursday that most Americans should get the Pfizer or Moderna vaccine, not the Johnson & Johnson vaccine, which can cause rare but serious blood clots.

Consultants of the US Centers for Disease Control and Prevention said that after Johnson’s vaccination, the strange blood clotting problem has caused 9 confirmed deaths-while Pfizer and Hyundai vaccines do not have this risk and seem to be more effective.

This is an unusual move, and CDC Director Dr. Rochelle Walensky must decide whether to accept the expert group’s recommendations.

So far, the United States has considered all three COVID-19 vaccines available to Americans as equal options because large studies have found that they all provide strong protection and early supplies are limited. Johnson’s vaccine was initially welcomed as a single-dose option, which is especially important for hard-to-reach groups like the homeless, who may not be able to get the second dose of Pfizer or Moderna they need.

But CDC’s consultants said Thursday that it’s time to recognize that a lot has changed since the vaccine was introduced a year ago. More than 200 million Americans are believed to be fully vaccinated, of which approximately 16 million have been vaccinated against Johnson & Johnson.

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