UPDATE: US pauses rollout of J&J’s COVID-19 vaccine amid reports of rare blood clots

UPDATE: Johnson & Johnson’s (J&J) COVID-19 vaccine will remain on hold after a health advisory panel in the US failed to reach a decision on the nationwide pause during a meeting yesterday.

The Centers for Disease Control & Prevention (CDC) convened a meeting of the Advisory Committee on Immunization Practices (ACIP) on Wednesday to review reported cases of blood clots in people who had received J&J's vaccine and to assess their ‘potential significance’.

The committee considered data on six cases identified in people who had received the J&J vaccine, which involved a rare type of blood clot known as cerebral venous sinus thrombosis (CVST).

However, committee members noted that existing data on CVST does not involve low platelet counts, which is what has been observed in the reported J&J vaccine blood clot cases.

As a result, the group made the decision to extend the pause and review additional data, instead of making a decision during the meeting.

According to Reuters, the ACIP is aiming to meet again in a week or ten days to further discuss the data related to the blood clot cases and the J&J vaccine.

“To be very frank I do not want to vote on this issue today,” said Beth Bell, professor of global health at the University of Washington and chair of the CDC working group.

“I don’t feel I have enough information to make an evidence-based decision,” she added.

In contrast, Doran Fink, deputy director of the division of vaccine and related product applications at the FDA said during the meeting: “Individuals, in consultation with their healthcare providers or vaccination providers, may arrive at a conclusion of favourable benefit-risk after taking into account demographic factors, risk exposure to SARS-CoV-2, and its severe outcomes, and access to other COVID-19 vaccines.”

13 April 2021: The US Food and Drug Administration (FDA) and Centers for Disease Control & Prevention (CDC) have issued a joint statement today recommending a pause on the rollout of Johnson & Johnson’s (J&J) COVID-19 vaccine.

The pause comes following six reported cases in the US of a rare and severe type of blood clot – known as cerebral venous sinus thrombosis (CVST) – observed in individuals after receiving the vaccine. In these cases, the rare blood clot type was seen in combination with low levels of blood platelets, known as thrombocytopenia.

As of 12 April, over 6.8 million doses of the J&J jab have been administered in the US.

The CDC is set to convene a meeting of the Advisory Committee on Immunization Practices (ACIP) on Wednesday to review the cases and assess their ‘potential significance’, while the FDA will review the analysis and also investigate the cases, the regulatory agency said in a tweet.

The FDA added that the pause is due to ‘an abundance of caution’ as it reviews the blood clot cases.

‘Right now, these adverse events appear to be extremely rare. COVID19 vaccine safety is a top priority for the federal government, and we take all reports of health problems following COVID-19 vaccination very seriously,’ the FDA said in the statement.

According to The New York Times, all six cases of rare blood clot events occurred in women aged 18 to 48 who had had the J&J vaccine.

Health officials in the US are reportedly concerned that clinicians may not be trained to identify the rare disorder, with the FDA and CDC saying in their joint statement that the ‘treatment of this specific type of blood clot is different from the treatment that might typically be administered’.

‘Usually, an anticoagulant drug called heparin is used to treat blood clots. In this setting, administration of heparin may be dangerous, and alternative treatments need to be given,’ they added.

The European Medicines Agency’s (EMA) Pharmacovigilance Risk Assessment Committee (PRAC) has also started a review into reports of people developing blood clots after receiving the J&J COVID-19 vaccine.

This includes four ‘serious cases of unusual blood blots with low blood platelets’ - one occurred in a clinical trial and three occurred during the US rollout of the vaccine.

‘These reports point to a ‘safety signal’, but it is currently not clear whether there is a causal association between vaccination with COVID-19 Vaccine Janssen and these conditions,' said the EMA.