Europe approves vaccine to stop next pandemic | Society

In the wake of the traumatic disaster caused by the coronavirus, scientists and governments around the world are tirelessly monitoring any threat that could lead to another pandemic. And all eyes turned to one usual suspect: the flu virus. Another reason to do this is the worst episode of bird flu ever known, which is still ongoing and has caused hundreds of millions of deaths since 2021…

In the wake of the traumatic disaster caused by the coronavirus, scientists and governments around the world are tirelessly monitoring any threat that could lead to another pandemic. And all eyes turned to one usual suspect: the flu virus. Another reason to do this is the worst episode of bird flu ever known, which is still ongoing and has caused the deaths of hundreds of millions of birds and some alarming infections in mammal species since 2021. Many experts fear that the pathogen will mutate and adapt to humans. “This bird flu is the sword of Damocles that hangs over us permanently. We must not ignore this because it could become the next pandemic,” says Daniel López Acuña, former director of health crisis action at WHO.

The European Medicines Agency (EMA) announced on February 22 the approval of a pre-pandemic vaccine that, if an avian flu crisis does occur, will be a key tool to confront the crisis and save millions of lives. The agency actually approved two formulas, although both could be considered slightly different versions of the same drug. The first, already completed and which can be manufactured immediately, is based on a known virus already circulating among birds. The second is the future, a vaccine that will be produced using the same procedure, but adapted to the form of the virus that causes the pandemic tomorrow.

“This is significant progress,” says Raúl Ortiz de Lejarazu, honorary director of the National Influenza Center of Valladolid. “The vaccines already approved will allow us to respond almost immediately to a possible pandemic, allowing us to take earlier action than coronavirus. “In addition, it is a new vaccine thanks to a production system that uses culturing the virus in cells rather than eggs, which gives it a big technical and logistical advantage,” says this expert.

The first of two vaccines approved by the EMA is called Celldemic. “It is based on a strain of avian influenza that circulated in turkeys in 2005 and produces a very effective immune response against the virus currently circulating,” explains Inmaculada Casas, head of the Laboratory of Respiratory Viruses and Influenza at the National Center for Research. Microbiology (CNM).

The vaccine uses two proteins on the surface of the virus, called hemagglutinin and neuraminidase, which in their numerous combinations (18 types of the first and 11 types of the second) form different types of pathogen and give them their effectiveness. name (H5N1 in the current avian influenza virus). It is these proteins, called subunits, that trigger the immune system’s response.

There are already veterinary vaccines for birds against the current avian influenza, but this is the first approved vaccine that protects humans. According to the EMA, “it is intended for immunization during outbreaks of influenza caused by animals, including when public health authorities anticipate a possible pandemic.” “The goal is to protect risk groups such as poultry workers and their contacts (family, friends…),” Casas adds. Currently, when deemed necessary, these groups are immunized with seasonal influenza vaccine, which, although at a lower level, also provides some protection.

Incellipan is the name of the second approved vaccine, “intended for use only when an influenza pandemic has been officially declared,” according to information provided by the EMA. “In fact, in this case, the production system or platform is approved, since the subunits (hemagglutinin and neuraminidase) of the virus that could cause a future pandemic are not yet known,” explains Ortiz de Lejaras.

A representative of the Spanish Agency for Medicines and Health Products (AEMPS) clarifies that this type of approval can be carried out because “although the strain may change, it will be in the same form of the virus and therefore it will be very similar.” This is what allows regulatory authorities to pre-test effectiveness and safety, as well as approve doses, recommendations for use…

The two vaccines will be given in two doses three weeks apart and are indicated for adults and children over six months of age. The most common side effects in adults are local pain at the injection site, fatigue, headache… Young children, six months to six years, may also suffer from fever, irritability and temporary changes in sleep patterns and appetite.

The pharmaceutical company that developed both vaccines is CSL Seqirus, one of the largest vaccine manufacturers in the world. The company did not respond to questions from EL PAÍS.

All the experts interviewed emphasized the significant changes that the system for producing new vaccines involves cultivating viruses in cells rather than in vaccines. “You forget about the hundreds or billions of eggs needed to produce the doses,” concludes Fernando Moraga-Llop, a spokesman for the Spanish Association of Vaccinologists (AEV).

The first step in producing a flu vaccine is getting the virus it is intended to kill to replicate. Traditionally this was done by inoculating them into fertilized chicken eggs. Subsequently, the resulting viruses are processed to isolate subunits (hemagglutinin and neuraminidase) that will be used in doses. “But this requires very complex logistics at all levels to always have fertilized eggs in the quantities and quality conditions you need. And, in addition, it has a big risk: in the event of an avian influenza pandemic, it is quite possible that there will be outbreaks in laying poultry farms, which could create a shortage scenario at the worst moment,” illustrates Ortiz de Lejarazu.

The egg culture also has two other problems, adds Moraga-Llop: “By inoculating it into chicken eggs, you force it to reproduce in a different host species, which can cause adaptive mutations that make vaccines less effective in humans. And in some patients it can also cause problems due to egg allergies.”

On the other hand, cell culture avoids all these limitations. “It’s made from mammalian cells. It can be stored in the laboratory at 80 degrees below zero and takes up very little space. When you need them, in a very short time you can have millions and millions of culture vials ready to produce vaccines. All this gives you enormous flexibility, scalability and speed. If currently about 1.5 billion doses of flu vaccine are produced annually, then with cell cultures we could easily reach 6 billion,” says Ortiz de Lejarazu.

Now that most of the technical challenges associated with vaccine development and production have been resolved, some questions remain: how governments and international organizations should use this tool to keep the world’s population safer. According to López Acuña, there is still a lot to be done in this area: “It is necessary to agree on a global production plan that envisages and ensures the production and distribution of the necessary doses throughout the planet. Consideration should also be given to creating a strategic reserve of vaccines for use in the early moments of a crisis. These are two key issues that countries and the European Commission must resolve within the framework of the World Health Organization (WHO),” concludes this expert.