Messenger RNA-based COVID-19 vaccines, such as those from Pfizer-BioNTech and Moderna, can be refrozen without losing immune efficacy, according to Hospital del Mar and University Pompeo Fabra (UPF) research, which allows for the expansion Availability of vaccination in countries with unstable medical infrastructure.
Santi Grau, Director of Medicines at Del Mar Hospital, explained that this ability to freeze injections allows vaccines to be processed in a centralized location, syringes prepared for use, and refrozen and transported. Vaccination that ensures its effectiveness.
The study, published in the journal Vaccines, could represent a “very important step” in advancing vaccination worldwide, particularly in developing countries, by simplifying and reducing the processing and transportation of finished vaccines, according to the researchers. Necessary infrastructure in host countries.
To test whether the Pfizer BioNTech and Moderna vaccines could be refrozen after preparation for syringes, the researchers used waste from vaccination centers that had been discarded but processed according to specifications.
One portion was administered to laboratory mice under standard conditions and as recommended by the manufacturers. The second group was frozen at -20°C for one month prior to injection into mice, and the third group was frozen at -80°C for the same period prior to injection.
In all cases, the animals developed the same immune response to SARS-CoV-2, without secondary effects, and in turn underwent messenger RNA stability assays with completely normal results.
Minimizing vaccine waste
“The fact that vaccines can be refrozen can be a huge step forward, allowing us to maximize the potential of all reconstituted vials and reduce their waste,” Grau emphasized.
According to the World Health Organization (WHO), 240 million doses were lost in Europe and Japan alone, and some of the doses sent to developing countries under the COVAX initiative could not be used due to expiration problems.
This has led to large disparities in vaccination coverage, approaching 70% in developed countries and less than 12% in less favored countries.
“For this reason, simplifying their preparation remains a challenge to avoid unnecessary dose loss,” Grau emphasized, noting that the option of refreezing the vials after their preparation can manipulate vaccine vials in the country. dispenser, freeze syringes and send to the destination for immediate use, without the need for large infrastructure.
According to Grau, the shelf life of frozen vaccine is at least one month. “The processing and refreezing of Comarty vaccines from Pfixer BioNTehc and Spikevax Moderna does not destroy the messenger RNA and its properties are the same in the three experimental conditions evaluated,” summarized Julana Magri, researcher. Translational Clinical Research Program Hospital del Mar Medical Research Institute (IMIM).
Rafael Maldonado, coordinator of the UPF Neuropharmacology-Neurofar research group, emphasized that “no significant side effects were detected in animals that received samples processed under conditions other than those indicated by the manufacturers regarding the possibility of refreezing them.
Hospital del Mar’s head of pharmaceutical services, Olivia Ferrandez, said the findings could be applied to other types of vaccines and “could facilitate their distribution both in large cities and in rural areas.”
The team that created this work showed in previous work that these vaccines, previously prepared for injection into syringes, could be transported at room temperature and under maximum safety conditions for at least three hours.
Source: El Diario