COVID-19 vaccines: Infographic overview

As 2020 drew to a close, news that COVID-19 vaccines were likely to be approved soon brought relief to many. For some, however, the news spurred anxiety about whether the vaccines would be safe. In this infographic, Nature Middle East offers a broad overview of vaccines, how they work, and how the COVID-19 vaccines fit into the picture.

The basic principle of vaccination is to prime the immune system so it is better prepared to meet a pathogen. Historically, the earliest way to accomplish this was to get a mild infection that conferred immunity to a stronger disease; for example, exposure to cowpox to prevent getting the much more deadly smallpox. Modern approaches use weakened or inactivated viruses, or even fragments of a virus, but the principle remains the same: safely expose the immune system to a pathogen so immune cells learn to recognize it and can react quickly and effectively the next time it appears.

In the case of COVID-19, some of the vaccines use a new technique based around messenger RNA (mRNA). In this approach, patients are never exposed to the virus, even in a weakened form. Instead, the vaccine carries mRNA from a key virus gene that makes the spike protein. Once inside cells, the mRNA serves as a template to make the spike protein, and our immune system then learns about it and is ready to fight off the virus. The mRNA template is then quickly degraded by our normal cellular processes.

When enough people are vaccinated, a disease can no longer spread through the population. That’s how vaccination campaigns have helped bring many diseases under control. COVID-19 vaccines have been developed on an accelerated timeline because of the exceptional circumstances, but they nevertheless went through the entire regulatory review and approval process. Though there will be immense logistical challenges in ensuring that everyone has timely access to a vaccine, we are one step closer to a post COVID-19 world.

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