VACCINES are akin to a cheat sheet for someone who is preparing for a big test.
Universiti Tunku Abdul Rahman (UTAR) Medicine and Health Sciences Faculty lecturer Dr Kang Waye Hann, who used this analogy, said once injected, the body’s immune system would learn how to handle the pathogen affecting the body.
“Most vaccines contain a weakened or dead version of the virus they are meant to protect against, while some carry only the proteins found on the virus’ surface.
“When the body comes into contact with the real virus, it knows how to protect against it and can set to work gobbling up the viruses before they can do too much damage, ” he said during a “Covid-19 Vaccine: To Vaccinate or not to Vaccinate?” webinar.
The two-hour programme was organised by UTAR’s Centre for Research on Communicable Diseases and Soft Skills Competency Department.
Dr Kang explained how a human’s immune system would act as the body’s natural defence to identify and destroy any foreign organisms or pathogens as well as neutralise toxins produced by certain bacteria.
“Among the responses are fever to elevate body temperature to stop pathogens from breeding, vomiting, diarrhoea, sneezing or coughing to eject the pathogens out of your body.
“Other immune responses to infection are body ache, fatigue and nausea, ” he said, adding that there were some bugs that could not be stopped by our immune system, thus the need for vaccines to boost our defence.
Dr Kang said vaccines would also help with herd immunity against viruses.
“When enough people develop resistance to a disease by getting a vaccine, the chance of a virus infecting someone else and spreading drops to near zero.
“This was how polio went from a disease that was infecting thousands of people in the past to one where very few cases are reported worldwide now.
“Vaccines provide herd immunity by giving indirect protection to individuals who cannot be vaccinated due to various reasons, ” he added.
Dr Kang said vaccines, just like other pharmaceutical products, undergo extensive testing and review for safety and efficacy in the laboratory, in animals and in three-phase clinical trials.
“Once they are proven to be effective, only then will they be submitted for approval.
“After vaccines are marketed, there will be post-licence surveillance to monitor their safety and any adverse events associated with their use.”
Some common side-effects or reactions like fever could be part of the immune response to the vaccine, he said.
The National Covid-19 Immunisation Programme is in progress, with vaccines being given to frontliners in the first phase.