Making the vaccine more difficult than Hollywood shows | Health

A vaccine is often the solution in the Hollywood representation of contagious disease outbreaks. The fictitious vaccine is created on the fly and with little or no testing, it is given to the public.

Nothing could be further from reality, as vaccine development is a highly regulated process that generally takes 10 to 15 years.

The first step is always to learn about the germ and how it causes the disease. Researchers identify the weaknesses of the germs and develop candidate vaccines to exploit them.

The candidates are then tested on animals in which the germ causes a disease similar to that in humans. It is often difficult to create such animal models, but necessary to demonstrate the potential effectiveness of a candidate. In addition, the safety of promising candidates is tested in several different animal species. It usually takes four to six years to reach this point.

The only way to really know if a candidate is safe and effective is to test it in humans. Human trials can only start if the animal data are convincing.

The tests are divided into three phases. During phase 1, the candidate is administered to a small group of adults, usually 20 to 80 years of age. They must be in very good health to best manage the harmful effects if they occur. The subjects are generally tested in groups, the first group receiving a low dose. If the group is doing well, the next group is tested at a higher dose and so on until the desired immune response is reached.

The main objective is to test safety and tolerability, but information on the immune response is also collected. The knowledge acquired is used to move on to phase 2.

Phase 2 consists of testing the selected dose on several hundred subjects. The health of the subjects is similar to that of the general population, except that they must be free from chronic health problems. The greater number of subjects reveals less common side effects.

Phase 2 studies often include other target populations such as the elderly and children. Typically, this phase is designed to show that the candidate is protective either by showing that it is preventing disease or inducing levels of protective antibodies. Most candidate vaccines fail at this stage and do not progress to phase 3.

Thousands of subjects are tested in phase 3 to identify rare side effects. Usually, subjects are followed for 18 months after vaccination to ensure long-term security. In total, human tests generally take five to ten years.

So to answer the million dollar question: when will we get a COVID-19 vaccine? Fortunately, phase 1 safety trials are underway, bypassing the first four to six years of preclinical assessment required for routine vaccine studies.

This head start is explained by the fact that we already know a lot about the study of epidemics caused by other coronaviruses (MERS and SARS). The rapid identification of COVID-19 and the sequencing of its genetic code have been possible due to recent technological advances.

The types of innovative vaccines that can be produced quickly have been developed for years. However, the time required for human testing can only be reduced too much. Optimistic estimates concern a COVID-19 vaccine approved in 18 months.

Although this does not correspond to the silver screen scenario, it would be a vital achievement.

Smarts vaccine is written by professors at the Sealy Institute for Vaccine Sciences. Megan berman, associate professor of internal medicine, and Richard Rupp, professor of pediatrics in the medical branch of the University of Texas. For questions about vaccines, send an email to [email protected].