Federal health officials are investigating “a handful” of new, unconfirmed reports which have emerged after Johnson & Johnson injections were paused nationwide, to find out whether or not they could be circumstances of a uncommon, critical blood clotting dysfunction that triggered the pause, the director of the Centers for Disease Control and Prevention mentioned Monday. It is unclear as yet whether the vaccine was responsible for the authentic few circumstances.

“Right now, we are encouraged that it hasn’t been an overwhelming number of cases but we are looking and seeing what has come in,” the director, Dr. Rochelle Walensky, mentioned at a White House information convention on the pandemic.

Last week, federal health officials mentioned they wished vaccine recipients and medical suppliers to remember of the authentic circumstances and to report any incidents of critical antagonistic reactions to the pictures. Health officials referred to as for the pause after six girls ages 18 to 48 developed the blood clotting dysfunction inside about one to a few weeks after Johnson & Johnson injections. One died, and as of final week, a second remained hospitalized in important situation.

On Wednesday, two extra circumstances had been added to the listing: a seventh lady, and a person who participated in Johnson & Johnson’s scientific trial. Seven of the eight recipients had blood clots in the mind. The clotting dysfunction appeared to be mixed with low ranges of platelets, blood cells that sometimes forestall clotting. The circumstances had been reported both to the C.D.C.’s database or on to Johnson & Johnson.

Dr. Walensky mentioned Monday that officials are pursuing the more moderen reports “and verifying whether they do in fact reflect a true case.” Officials will current their findings on Friday to an C.D.C. advisory committee assembly, she mentioned. The committee’s specialists may suggest lifting the pause, modifying it or limiting the use of the vaccine.

Dr. Anthony S. Fauci, a White House medical adviser, mentioned on NBC’s “Meet the Press” on Sunday that he seriously doubts the vaccine will be permanently pulled. But he mentioned, “I do think that there will likely be some sort of warning or restriction or risk assessment.”

Experts are attempting to find out whether or not the uncommon blood clotting dysfunction is in actual fact linked to the Johnson & Johnson vaccine. The investigation follows actions by European regulators who concluded that one other vaccine — developed by AstraZeneca and primarily based on an analogous know-how — could also be linked to a uncommon clotting dysfunction.