The FDA certification of the Baltimore plant has now been delayed while inspectors investigate issues of quality control, sharply reducing the supply of Johnson & Johnson vaccine. The sudden drop in available doses has led to widespread complaints from governors and state health officials who were expecting much larger deliveries of Johnson & Johnson’s vaccine this week.
States have used the vaccine in a wide variety of settings, including on mass vaccination sites and on university campuses. The one-shot approach of the vaccine proved popular and officials targeted it at passing, rural and isolated communities where follow-up of a second dose is more complicated.
It is common for regulators to investigate ‘safety signals’ in new vaccines and other medical products. Quite often it seems that the signals are not worrying. But concerns about Johnson & Johnson’s vaccine reflect concerns about AstraZeneca, which European regulators began investigating last month after some recipients received blood clots.
Of the 34 million people who received the vaccine in Britain, the European Union and three other countries, 222 experienced blood clots associated with a low platelet count. The majority of these cases occurred within the first 14 days after vaccination, mostly in women under 60 years of age.
On April 7, the European Medicines Agency, the main regulatory agency, concluded that the disease was a very rare side effect of the vaccine. Researchers in Germany and Norway published studies on April 9 that suggest that the AstraZeneca vaccine, in very rare cases, causes people to make antibodies that activate their own platelets.
Nevertheless, regulators have argued that the benefit of the vaccine – not getting people infected with the coronavirus, or the few who get Covid-19 from the hospital, far outweighs the small risk. Countries in Europe and elsewhere have continued to give the vaccine to older people, who are at high risk for serious diseases and death due to Covid-19, while being restricted to younger people.
Both AstraZeneca and Johnson & Johnson use the same platform for their vaccine, a virus called an adenovirus. The Australian government announced on Tuesday that it would not buy Johnson & Johnson vaccines. They cite Johnson & Johnson’s use of an adenovirus. But there is no clear reason that adenovirus-based vaccines can cause rare blood clots associated with low platelets.