How vaccines train your body to stay alive

Now that Covid-19 vaccines are finally here, have you wondered how they’re made and efficacy determined? Well, for starters the vaccines being distributed were emergency authorization by the World Health Organization (WHO) and are safe in developing immunity against SARS-Cov-2, the virus that causes COVID-19.

 Vaccines contain tiny fragments of the disease-causing pathogens-which could be fungi, bacteria, worm and in the case of Covid-19, a virus. This pathogen is covered in an antigen, basically a small part of the disease-causing organism that the body learns to fight without one getting sick. For safety, vaccines have preservatives to prevent them from getting contaminated when the vial that stores them is opened especially if the vaccine is not a single-use vaccine.

 Vaccines also have stabilizers that prevent chemical reaction from occurring within the vaccines. Other vaccines have adjuvants that help improve the immune response to the vaccine.

 Vaccines go through extensive testing with an experimental vaccine first used in animals to evaluate its safety and potential to prevent disease. Clinical trial vaccines are then tested on people in three phases: Phase One is given to a sample size of volunteers to assess safety and efficacy in generating an immune response.

Results are later used in determining the right dosage. In Phase II, the vaccine is given to hundreds of volunteers who are monitored for any side effects to further assess its ability to generate an immune response. Participants have similar characteristics like age and sex. Also, some volunteers receive the vaccine and others do not, which allows for comparisons and conclusions about the vaccine

 In phase III, the vaccine is given to thousands of volunteers where more data is drawn to ascertain its safety and efficacy-with a 70 per cent efficacy being good enough.

When the virus causing diseases enters our bodies, they recognize it as foreign and thus develops an immune response by creating antibodies specific to the virus or bacteria. Vaccines, on their part, train the immune system to create antibodies, just as the body does when it’s exposed to a disease.

After vaccination, it takes at least ten to 14 days for the body to develop immunity. Besides vaccines, WHO also recommends clean water and sanitation as the other effective options in keeping disease away.

As for the Covid-19 pandemic, a country attains herd immunity when at least 60 to 70 per cent of the population are immune to the virus-a fete mostly achieved through mass vaccination.

Source: WHO