Canada has become the first country in the world to delay the expiration date of a coronavirus vaccine. This is a batch of AstraZeneca serum that expired last Monday, the 31st, and another that will expire this month, more than 60,000 doses in total. The shelf life of these vials has been extended for 1 month; that is, from the initial 6 months up to 7 months.
The measure, adopted by the Canadian authorities after the pharmaceutical company analyzed both items and guaranteed their “efficacy and safety” in that additional month, opens up new possibilities at a time when millions of doses around the world are approaching their date of expiration. Part of the problem, just as in Canada, is due to the “big stoppage” that occurred in last March in many countries with the use of the AstraZeneca vaccine after the first episodes of thrombi, very rare yet serious, related to this drug were known.
Most of the vials that may be affected will be part of large donations from rich to less developed countries, such as the one announced by the United States: 80 million doses throughout this month. The great risk is that they end up being destroyed, as it happened in Malawi (20,000 doses) and South Sudan (59,000), whose health systems were not able to manage all the units received weeks before from South Africa.
To short a period
Miriam Alía, head of vaccination at Doctors Without Borders (MSF), explains: “Some recipient countries have complained that the doses come with a very short expiration date, which does not allow them to activate their vaccination plans in a solvent way because they do not know when they will receive the donations. The first batches of AstraZeneca have come out with a six month expiration period. During this period, they must be transported to their destination and the vaccination campaign organized. If, in addition, the vaccines pass through more than one country because they arrive as a result of a donation, that six-month period is very short”.
The federal government of Canada -which, like Spain, has opened the possibility that those who received a first dose of AstraZeneca can complete the regimen with a second dose of messenger RNA (Pfizer or Moderna – mobilized all its resources last week to prevent AstraZeneca doses, which were nearing their expiration date, would be destroyed. On the one hand, it made available to the provinces means of “coordination and logistics” so that the roads that were not going to be used in some could reach others as soon as possible. On the other, and in collaboration with the pharmaceutical company, the government studied the possibility of prolonging the useful life of the serum.
Finally, the federal Ministry of Health announced, last weekend, that it had received a document from AstraZeneca that guaranteed that “the quality, safety, and efficacy of the batches in question would be maintained for 1 more month” and that this decision was based on “solid scientific data”.
A spokesperson for the pharmaceutical company explained to this newspaper: “The decision taken in Canada was based on a thorough review of the scientific and stability data, which showed that the quality, safety and efficacy of 2 batches would be maintained for 1 more month, for a total of up to 7 months. Because this was based on a specific request, these data are not being considered for other batches beyond the 2 referenced in the Health Canada extension”, reports Rafa de Miguel.
It is not foreseeable, at least for now, that Spain could be affected by this problem. In addition to the fact that the shipments finally received are smaller in quantity than initially expected, the first doses of AstraZeneca arrived in the country in mid-February, so there are more than 2 months left to reach the expiration date shown on the label.
Expiration dates must be respected
Fernando Moraga-Llop, vice president of the Spanish Vaccination Association, clarifies that “the expiration date of vaccines, like that of other medicines, must always be respected, unless there are specific tests that guarantee their stability carried out by the manufacturer and endorsed by the regulatory body. Administering them after the deadline, in principle, does not have to carry a risk of toxicity, but the loss of effectiveness is important”, he adds.
The experts consulted admit that good communication of these changes is essential to avoid misgivings among the population. “It is a key policy that companies and regulatory agencies provide information always based on scientific evidence and in a clear and transparent way”, explains José Luis Barranco, spokesman for the Spanish Society of Preventive Medicine, Public Health and Hygiene.
“These kinds of changes are not so uncommon. With Pfizer, for example, we have already seen twice how the time they can be defrosted was prolonged. We cannot forget that they are vaccines that have been developed at high speed and safety has been prioritized. From now on it is possible that these and other characteristics will become more flexible as it is seen that it is safe and effective. It is true that delaying the expiration date can, from the outset, arouse some objection; but well done and with proper communication it should not be a problem”, adds Barranco.
Following the destruction of tens of thousands of doses in Malawi and South Sudan, the World Health Organization (WHO) has released a specific document on how to proceed in these situations. The text refers to the AstraZeneca vaccines produced under license by the Serum Institute of India, which were affected. The body’s position is that, despite several ongoing investigations and unless there are studies such as the one in Canada that corroborate the efficacy of the vials, these “should not be administered”.
The AstraZeneca vaccine will be one of those donated in the upcoming months. The first reason is its enormous global manufacturing volume due to the dozens of manufacturing licenses signed by the Anglo-Swedish laboratory with various countries. The second reason, its easy storage in a conventional refrigerator (just keep it between 2 and 8 Celsius degrees). Africa González, professor of immunology at the Center for Biomedical Research of the University of Vigo, adds a third one: “It is a vaccine that uses an adenovirus as a vector and is, therefore, much more stable than others such as messenger RNA”. Some studies, not yet completed, suggest that the shelf life of this type of serum could exceed one year.
Scientific and health criteria
González regrets that “many of these problems could have been avoided if they had been thought globally, with scientific and health criteria, and not with the logic of rich countries first and poor countries later.” “My opinion is that such purchases should have been centralized through the WHO and, then, gradually develops a strategy for age groups and risk, just as countries have done it before but now for everyone. Not having done so is turning against us, as we see with variants that have arisen in countries with less vaccinated population, but that end up affecting us equally”, adds this expert.
Irene Bernal, a researcher at the independent organization “Salud por Derecho” (Health by Own Right), predicts problems in the upcoming months in countries with health systems already weakened by the pandemic, which may be difficult to make an adequate distribution of vaccines received irregularly, in large volumes and with a close expiration date. “Although donating is not the solution to fair and equitable access, the countries that commit to do so must ensure a sufficient margin of time for its global distribution and administration in the recipient country. If all this is not done, the effort will be useless. Expiration is a matter that must be taken into account when signing contracts”, she concludes.
