Covid vaccines: From having too few to having too many

When the pandemic began in 2020, Covid vaccines were a faraway dream. When they were available, a year later, they became a precious and highly coveted object, reserved for priority groups. Today, they are a problem for rich countries who don’t know what to do with all the vaccines they purchased. Their contracts with pharmaceutical companies are secret, but in 2022 and 2023, countries like Spain budgeted over a billion euros to have enough doses for the entire population. Half of those vaccines have gone unused.

In Spain, 105 million doses have been injected since the beginning of the vaccination campaign in December 2020. The country has received 103.5 million vaccines that have not been injected, according to data from the Ministry of Health. The booster campaign has not had the same response as previous ones: since it began in the fall, only 60% of people over 60 years old, 7.5 million people, have received it. It seems that the vast majority of the vaccines purchased will never be distributed.

The Ministry of Health argues that it is necessary for Spain to have enough stock to be able to face potential changes in the epidemiological situation. “All countries have strategic reserves of medicines that are stored in anticipation of potential unforeseen events and that, fortunately, in some cases it is not necessary to use. It is part of the necessary preparation against public health threats,” said a spokesperson.

The problem is that these reserves have an expiration date. They can go bad if they are not used, as has already happened with 14 million first-generation doses, which were discarded when omicron boosters arrived. Now, the latter are at risk of expiring. The Ministry of Health notes, however, that the expiration date is not set in stone: it has been modified once it was verified that the vaccines remain stable for longer than initially planned. “The date corresponds to the period of validity authorized by the EMA [European Medicines Agency] and is likely to be extended as the incumbent laboratories provide new stability data over time and request extension of the period of validity,” adds the spokesperson. It is not clear how long they can last in storage.

EU countries have been considering the problem for months. In a response to the European Parliament this Wednesday, the European Commissioner for Health, Stella Kyriakides, explained that the Commission is working with the member states and the industry to find “a solution to the imbalance between demand and supply” of vaccines. “Several amendments to the purchase agreement with BioNTech-Pfizer have already been approved to allow us to partially cover the needs of member states. Nonetheless, the Joint Negotiating Team continues to negotiate a reduction in the number of doses to be delivered in 2023,″ she said.

This agreement consists of delaying until 2026 deliveries that were scheduled before the end of the year, as the Financial Times reported this week. But that does not solve the problem of the doses in danger of expiring, since international agreements establish that they cannot be given away or sold once they have been received. (The Spanish government has donated 70 million doses which had not yet reached Spanish soil.)

Is a fourth dose necessary?

Authorities had purchased vaccines anticipating that all Spaniards would need new doses, as Minister Carolina Darias stated in June. That is not the case today. As Marcos López Hoyos, president of the Spanish Immunology Society, explains, the first booster, added to the two initial doses and the natural infection that “the majority of the population” has suffered, makes a fourth injection unnecessary for healthy young people.

In Spain, the health authorities recommend the fourth dose, or second booster, only to people over 60 years of age and to those who have a pre-existing health condition that makes them more vulnerable to the virus. The vaccination campaign for those populations began last fall. Later, in December, the ministry authorized the rest of the population to receive the booster if they needed it for administrative reasons (to enter a country that requires it, for example), as well as for anyone who wanted to receive it, as long as they were older than six years old.

The policy has generated some confusion among the public. The fact that anyone can receive the dose does not mean that it is recommended for everyone or that it will benefit them. The effects of the three doses, especially for those who have been infected since the arrival of omicron, have proven to be sufficient protection to prevent complications in the event of a new contagion.

To the question of whether a fourth dose is necessary, the biologist Nuria Izquierdo-Useros said a few weeks ago in this newspaper: “At this moment, when we talk about messenger RNA vaccines, what we know is that compared to the second dose, the third increases the immune response for a longer time. However, the fourth dose does not exceed the maximum levels obtained with the third, and its effect wears off after about three months after vaccination. Therefore, the time to get vaccinated should coincide with situations in which community transmission is high and the risk of contagion is very high. In this sense, the next booster doses of the vaccine should be planned to coincide with times of the year with greater risk, as is the case with the flu vaccine.”

Scientists are now studying the duration of the immunity generated by both vaccines, infection and their combination. “In the future it will be necessary to see if the COVID behaves seasonally and how long that immunity lasts in people. We are carrying out studies to verify different scenarios and, based on that, decide if there are groups that need seasonal vaccination each year,” says López Hoyos. For people without immunodeficiencies who are vaccinated and boosted, and who have had an omicron infection, she adds, “Another dose is not necessary for the moment.”

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