A new report this morning says Johnson & Johnson asked other vaccine makers to help it investigate the risk of blood clots linked to its coronavirus vaccines.
According to a Wall Street Journal report, Pfizer and Moderna declined.
AstraZeneca is reportedly the only COVID-19 vaccine maker that agreed. It's also facing a small number of reports of blood clots in people who have received its vaccine.
Earlier this week, officials called for state vaccine sites to pause administering Johnson & Johnson shots because six people reported blood clots.
More than 7 million people have gotten the single-dose shot.