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Why fast-tracking COVID-19 vaccines can be dangerous

Why fast-tracking COVID-19 vaccines can be dangerous
Now, the scenario looks hopeful with many contenders now in almost the final stages of vaccine development.

The speed at which researchers and pharma companies are developing the COVID-19 vaccines has been described as "unprecedented" by many experts.

Written by Longjam Dineshwori |Updated : July 15, 2020 2:58 PM IST

Vaccination seems to be the only way to stop the spread of COVID-19 pandemic, which has infected over 12 million people and claimed over 5 lakh people worldwide. Unfortunately, we don't have a vaccine yet for SARS-CoV-2, the virus that causes COVID-19. Scientists are racing against time to find a cure for the viral disease and countries around the world are breaking the norms to bring out a safe and effective vaccine against COVID-19 in the shortest time. Nearly 150 potential COVID-19 vaccines are being tested around the world, according to the World Health Organization (WHO). Out of this, 17 candidates are in clinical trials, with one already in Phase 3 and two others likely to enter in July.

While WHO chief scientist Soumya Swaminathan said that there will be one or more safe and efficacious vaccines by next year, a few companies are predicting that their vaccines could be ready to go into production globally in the next two-three months. A vaccine candidate developed by the University of Oxford is already in the final stages of clinical trials. The researchers are expecting the results of the clinical trials by August or September and the vaccine on the market by October. US President Donald Trump is also expecting one by the end of the year. India is also not far behind the race. The country is aiming to launch its first COVID-19 vaccine candidate 'Covaxin' by August 15. But the speed at which the vaccines are being developed has left public health experts worried about their long-term safety and protection.

Stages of Vaccine development

Vaccine development normally takes more than 10 years and costs millions. It has to go through 5 stages of development

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  1. Discovery research (which may take 2-5 years)
  2. Pre-clinical (2 years)
  3. Clinical development. This further includes three phases: Phase I, Phase II, and Phase III to study the candidate vaccine's safety, immunogenicity, proposed doses, schedule of immunizations, and method of delivery. It may take 2-4 years.
  4. Regulatory review and approval (1-2 years)
  5. Manufacturing and delivery

The speed with which researchers and pharmaceutical companies are developing the coronavirus vaccine has been described as "unprecedented" by many experts.

Risks of fast-tracking a vaccine

Reducing timelines for vaccine development from years to months could mean missing information about long-term safety and protection, opined experts. Here are some possible risks of fast-tracking a Covid-19 vaccine:

  • The vaccines might be approved with incomplete data and analysis.
  • A fast-tracked vaccine will have unintended side-effects.
  • There is a risk of antibody-dependent enhancement (ADE). It occurs when the body generates antibodies that don't sufficiently neutralise the virus and instead encourage it to replicate, which exacerbates the disease.
  • Companies may not complete animal studies and move to human testing, which transfers extra risk to humans.
  • There are still many things researchers don't know about coronaviruses. Are antibodies protective? How long does immunity last? All these questions still remain unanswered. This is another concern with speedy vaccine development.
  • Fast-tracking vaccines also risks compromising assessments of immunological memory
  • A fast-tracked vaccine may be only partially effective as the focus has been shifted from the search for a drug that protects against disease to one that merely reduces disease severity.