A French study proved some syringes can actually extract 7 doses in Pfizer's Covid-19 vaccine vials. But global supply of adequate equipment is short.
As the world is trying to inoculate the maximum of vaccine doses, a group of pharmacists studied the efficiency of various syringes and showed the seventh dose could really be extracted from Pfizer vials. But the lack of adequate equipment can limit the optimization.
In January 2020, the European Medicines Agency officially approved that six doses of Covid-19 vaccines could be extracted from each Pfizer/BioNTech vial rather than five. Each vial indeed contain a little more than the quantity contracted as a precaution to make sure all doses are actually delivered. In theory, there are about 7.5 doses in each vial of 5 doses.
But Pfizer started to reduce the delivery of vaccines, claiming for example that the European Union bought a number of doses, and not vials. While the member countries were craving for getting more doses of vaccine, it spurred a lot of debate. However, behind the controversy and the business negotiations, the discussion showed that adequate material was also essential for top-quality healthcare services.
And the optimization of each vial is possible by using specific syringes that would limit the "dead volume" left inside. The volume left in a syringe is in fact smaller with some models, limiting waste of the precious liquid. Being able to extract 6 doses instead of 5 in each vial would account for a 17% increase in the number of vaccines administered to the population. It is a massive improvement. But extracting a seventh dose would even make each vial 29% more efficient.
Covid created a global shortage of low dead-volume syringes
In various places like in Korea, Spain, France, Finland or Belgium, health care providers realized that a seventh dose could be extracted. For instance, two Spanish nurses used needles usually meant to administer insulin.
A group of pharmacists working for a French hospital has tested several syringe configurations in March and corroborate in-field experience. It showed that out of 8 models tested, their syringes with needles already crimped onto it offered a lower dead volume, "allowing to extract up to seven doses from a single vial". Syringes with a dead volume smaller than 10 µL (0.01 mL) could extract a seventh dose. But such material has become in high demand. In fact, between 8 and 10 billion syringes are necessary for the world to be vaccinated against Covid-19 while less than the 2 billion syringes are usually used for vaccination and immunization every year.
In January, Brazil restricted its exports of syringes and needles. In February, the Health Minister of Japan Norihisa Tamura admitted the country would be unable to extract the sixth dose because it lacked adequate syringes. However in March, Japan allowed the used of syringes meant for insulin shots, although they are specific for subcutaneous rather than intramuscular injections. The United and the European Union also reported a shortage of needles. According to the Wall Street Journal, a U.S. Department of Health and Human Services spokeswoman acknowledged the supply was limited last May. Dr François Lesourd, who participated in the French study, told Newsendip that "we now have the adequate syringes to extract a seventh dose in France. But in the context of a global shortage, we are still testing the efficiency of various syringes from different suppliers".
The demand is high and the industry tries to ramps up its production. But it tends to neglect the usual production. "In France, we will soon lack the hypodermic needles, those we use for pretty much everything in hospitals, as everyone produces the needles for the Covid-19 vaccines", warned Dr Lesourd. The disruption caused by the pandemic has multiple collateral consequences.
Along with face masks, ventilators, medical oxygen or medical gowns, low dead-volume syringes are in fact another example during this pandemic that medical equipment is part of a complex chain in the efficiency of the healthcare systems.
Media sources and useful links:
- Maximizing number of doses drawn from multi-dose COVID-19 vaccines by minimizing dead-volume, Journal of Travel Medicine, March 2021, Free access
- Dos enfermeras valencianas logran sacar una séptima dosis de vacuna de Pfizer, Agencia EFE, February 2021
- Japan to allow use of insulin syringes for COVID-19 vaccines, Kyodo news, March 2021, Free access
- Covid-19 Vaccines Are Wasted as Special Syringes Run Short, The Wall Street Journal, May 2021, Limited access
- Ramping up vaccine production provokes a scramble for syringes around the world, The New York Times, May 2021, Limited access
- Ministério de Saúde vai adquirir mais de 100 milhões de seringas e agulhas, Brazil federal government, January 2021, Free access