Dr. Fauci felt little love from Republicans, however. He and Representative Jim Jordan, Republican of Ohio, reprised their heated clash from the last time Dr. Fauci testified before the panel in July 2020.
“You’re ranting again,” Dr. Fauci said at one point.
“I’m not ranting,” Mr. Jordan replied.
“Yes, you are,” Dr. Fauci insisted.
With worrisome new variants of the virus spreading, Dr. Fauci and the others repeatedly described all three of the federally authorized vaccines — from Johnson & Johnson, Pfizer-BioNTech and Moderna — as highly safe and effective.
The reports of blood clots were the second recent blow to the Johnson & Johnson vaccine. Earlier this month, an ingredient mix-up at a Baltimore manufacturing plant owned by Emergent BioSolutions ruined up to 15 million doses of the vaccine. The F.D.A. is now inspecting the plant to see whether any vaccine doses manufactured there can be released to the public.
- On April 13, 2021, U.S. health agencies called for an immediate pause in the use of Johnson & Johnson’s single-dose Covid-19 vaccine after six recipients in the United States developed a rare disorder involving blood clots within one to three weeks of vaccination.
- All 50 states, Washington, D.C. and Puerto Rico temporarily halted or recommended providers pause the use of the vaccine. The U.S. military, federally run vaccination sites and a host of private companies, including CVS, Walgreens, Rite Aid, Walmart and Publix, also paused the injections.
- Fewer than one in a million Johnson & Johnson vaccinations are now under investigation. If there is indeed a risk of blood clots from the vaccine — which has yet to be determined — that risk is extremely low. The risk of getting Covid-19 in the United States is far higher.
- The pause could complicate the nation’s vaccination efforts at a time when many states are confronting a surge in new cases and seeking to address vaccine hesitancy.
- Johnson & Johnson has also decided to delay the rollout of its vaccine in Europe amid concerns over rare blood clots, dealing another blow to Europe’s inoculation push. South Africa, devastated by a more contagious virus variant that emerged there, suspended use of the vaccine as well. Australia announced it would not purchase any doses.
About 7.7 million Americans had received the Johnson & Johnson vaccine, accounting for less than 4 percent of the more than 198 million doses administered across the country. The Pfizer and Moderna vaccines are in much greater supply.
Officials note that the blood clots are extremely rare; the handful of cases represent less than one in one million recipients, although that incidence estimate could go up if more cases are reported.
Biden administration officials say that the absence of the Johnson & Johnson vaccine might not have a major impact on the U.S. vaccination campaign. But if use of the vaccine is severely restricted worldwide, it could prove disastrous for the global vaccination effort.