FDA defends vaccine shelf-life extensions

The Food and Drug Administration has said it was following the latest approved safety information when it extended the shelf life of some batches of Pfizer Covid-19 vaccine to 15 months from nine.

The FDA was responding to a complaint from the Thailand Nursing and Midwifery Council, which expressed concern that the extension might affect people’s health.

Suchitra Luengamornlert, the council president, submitted a letter to the permanent secretary of the Ministry of Public Health on Jan 31 to outline the group’s concerns.

The letter referred specifically to the FDA approval of a shelf-life extension for Comirnaty 30 microgrammes dispersion for injection formula, PBS/Sucrose buffer vaccine manufactured in Germany, a source said on Tuesday. Comirnaty is the trade name of the vaccine developed by Pfizer and its German partner BioNtech.

Eight batches of the vaccine, totalling 4.8 million doses, had an original expiry date of Sept 30, 2022, nine months after the date of manufacture. The FDA approved a new expiry date of March 30 this year, for vaccines stored between -60 and -90 Celsius.

The nurses’ council had raised the issue for discussion at a meeting of the Association of Medical Technologists of Thailand on Jan 10. The meeting resolved that the council sent a letter to the FDA asking it to review its decision.

Members were concerned that the injection of “expired” vaccines with a shelf-life extension may affect people’s health and affect the image of the council as 80% of those who administered vaccine doses to people were nurses.

However, FDA secretary-general Paisarn Dunkum explained that the extension was based on academic information conveyed by an authorised agent from the vaccine manufacturer. As long as the vaccine is kept at a constant temperature -60 C, it can be used for 15 months from the date of manufacture.

If there were any reports regarding unsafe use of the expired vaccine, they would be taken into consideration to suspend use or recall lots that had problems, he said.

The new expiry dates for deep-freeze vials of the vaccines in question are set out on the website of the Paul-Erlich-Institut (Federal Institute for Vaccines and Biomedicines) in Germany. It says they can be used for up to 18 months if proper storage methods are followed.