If the current health crisis taught us anything, it is that time is short, and although the pandemic seems like an eternity and we wonder why the development of vaccines against COVID-19 takes, the reality is that laboratories and experts have never worked so fast.

Governments, pharmaceutical companies, research centers and universities around the world are working around the clock to develop an efficient way to combat SARS-CoV-2.

To this day the World Health Organization (WHO) registers more than 169 vaccine candidates in development, of which 27 are in phase 1, 14 in phase 2, 11 in phase 3 and 5 have been pre-approved for limited use according to the New York Times vaccine tracking.

What are the phases and why does the development of vaccines against COVID-19 take?

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For a vaccine to be approved and manufactured on a large scale, it is necessary that the entities that are developing it meet certain requirements and tests.

Each of these phases and the approximate development time of each one are described in broad terms below:

In the preclinical phase (2 years) tests are carried out on cells and if these are satisfactory, the vaccine is applied in mice or apes to see if they produce an immune response.

During the phase 1 (1 to 2 years) the vaccine is applied in a small number of people to verify its safety and dose, as well as to confirm that it stimulates the immune system.

For the phase 2 (2 to 3 years) are vaccinated to hundreds of people divided into groups, such as children, adults, the elderly, and the effects that exist in each of them are studied.

In the step 3 (2 to 4 years) the application of the vaccine leaflet is injected into thousands of people, of which some will receive placebos, and both the immune response, the effectiveness of the vaccine (that is, whether or not they are infected with the disease ), and the results are compared between those who received the vaccine and the placebo.

In this phase it is even possible to find side effects or allergic reactions to the vaccine.

Finally, in the approval phase (1 to 2 years), and with the records of the previous phases, the regulatory entities of each country can decide which vaccine will be administered in their territory. In Mexico, the entity responsible for this approval is the COFEPRIS.

This gives us an approximate total, at best, of 8 years between preclinical studies and approval of a vaccine.

There are also pre-approved vaccines

There are also pre-approved or limited-use vaccines, of which only China and Russia have agreed to use them without waiting for the results of phase 3.

This type of pre-approval might seem like a radical measure and few governments venture to use this method. However, there may be a combination between phases.

One way to speed up development is combine phases 1 and 2 in a single, that is, administer the vaccine to hundreds of people and monitor their reaction to it.

There are different types of vaccines

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Not all vaccines are developed in the same way and even not all are made equal. There are different ways to attack the virus and that determines the classification of vaccines.

Genetic vaccines: Vaccines with one or more coronavirus genes that are used to generate an immune response.

Viral vector vaccines: These types of vaccines contain a harmless virus type developed in laboratories that contains genes for the coronavirus. In this way the “fake” virus replicates in cells and generates an immune response to the “real” virus. The Russian Sputnik-V vaccine is of this type.

Protein-based vaccines: In this case, the vaccines contain coronavirus proteins, but no genetic information about it.

Some contain complete proteins, others, fragments of these. Within this classification are vaccines developed with nanotechnology which consist of capsules so small that they are tiny compared to the size of a cell.

Inactivated or attenuated coronavirus vaccines: These are developed with weak or dead coronaviruses that still contain the genes necessary for our immune system to develop its own antibodies.

The work of developing a vaccine

Each and every one of these phases, as well as the technology used to develop them, used to take years to complete, but today it has been possible in months. thanks to technological advances in biotechnology, computer simulation and medicine. Today more than ever we realize how much investment is required in science and technology.

The WHO works together with all entities involved in the development of the vaccine, as well as with civil and philanthropic societies, since its main concern is to give access to the most vulnerable people.

Through your initiative COVAX They seek to offer access to diagnostics, treatments and vaccines to attack the covid-19 pandemic.