- Do you have any idea what was the fastest vaccine ever developed? It was vaccine of mumps. It took four years to develop.
- Reports and analysis of cases indicates that coronaviruses do not tend to trigger long-lasting immunity.Researchers from Oxford University recently studied on a blood sample taken from recovered Covid-19 patients and found that levels of IgG antibodies which is responsible for longer-lasting immunity, became weak after few months.
- The genetic stability of the virus matters too. Some viruses like influenza, mutate so rapidly that vaccine developers have to release new formulations every year. Similarly, the rapid evolution of HIV is the reason we are still unable to develop a vaccine for the disease.
- The SARS-CoV-2 coronavirus seems fairly stable, but it is acquiring mutations too, slowly but it is, like all other viruses. Scientists have spotted some genetical changes in the virus’s protein “spikes”. If the mutation rate of the spike proteins becomes high, the antibodies produced by a vaccine will not be effective and might not combine with the virus to prevent infection.
Types of vaccines
- Live vaccines: Live vaccines are produced from weakened or attenuated form of the germ that causes a disease.
- Examples: measles, mumps, rubella, smallpox and chickenpox
- Inactivated vaccines: Inactivated vaccines are produced from a killed or inactive version of the germ that causes a disease.
- Examples: Flu, hepatitis A and rabies
Now let’s know – How are the Vaccines produced ?
- Phase one involves introduction of the vaccine into human population
- Phase two is the observation stage of immunogenic and toxicity results
- Phase three deals with the monitoring toxicity results in large scale
- Phase four is the data collection stage on adverse effects and long-term immunity
Major challenges to overcome for corona virus vaccine
- Ensuring vaccine safety: Several vaccines for COVID-19 have been tested in animals but most of the didn’t prevent infection though it improved the animal’s immunity. Some vaccines also caused lung damage. Still A COVID-19 vaccine is needed to be tested in human models for its safety.
- Long-term protection: Infection and re-infection with the same virus is being tested but as it is mentioned earlier the antibodies are falling weak after few months.
- Protection of older people: Older people are at higher risk of severe COVID-19. But clinical challenge is the older people usually don’t respond to vaccines as well as younger people.