AsianScientist (Apr. 13, 2021) – With their key role in overcoming some of humanity’s greatest scourges, vaccines are widely hailed as one of medicine’s greatest achievements. Consider the case of polio, a disabling disease caused by the poliovirus. For centuries, polio crippled hundreds of thousands of children each year. In the late 1980s, there were over 125 polio-endemic countries. After a concerted global effort to vaccinate against the virus, only two remain today: Afghanistan and Pakistan.
Between 2010 and 2015, the World Health Organization (WHO) estimates that vaccination prevented at least ten million deaths. As the world collectively reels from COVID-19’s devastating impacts, vaccines are our best chance at saving countless more lives and returning to some semblance of normalcy. It’s no wonder, then, that over 200 vaccine candidates against the SARS-CoV-2 virus are currently in development.
With the fate of humanity resting on a literal shot (or two), we dive deep into the science behind these medical marvels and take a look at Asia’s vaccine frontrunners.
When the immune system strikes back
- When viruses like SARS-CoV-2 invade our body, they hijack our cellular machinery and multiply.
- Specialized cells called antigen-presenting cells engulf the virus, displaying or presenting viral proteins on their surface later on.
- The presented viral proteins attract immune cells called helper T-cells that trigger a host of immune responses.
- B-cells are triggered to make antibodies that lock onto parts of the pathogen, called antigens. SARS-CoV-2’s spike protein, which it uses to enter the cell, is a key antigen targeted by vaccines.
- These antibody-coated pathogens are marked for destruction and engulfed by immune cells called macrophages.
Even after the infection goes away, its memory still lives on through the B-cells. Should the same pathogen invade the body once again, ‘memory’ B-cells now have an arsenal of antibodies that can be immediately released—making the antibody response faster and more effective the second time around.