The investigator should report all serious adverse reactions to the drug regulatory body Drug Controller General of India (DCGI), sponsor of the trial and the concerned Ethics Committee that approved the trial protocol within 24 hour of occurrence.
With the coronavirus pandemic showing no signs of abating, the success or otherwise of human trials has become very critical and a major cause for concern worldwide. With a number of human trials for Covid-19 vaccines and drugs taking place across many countries, there is the possibility of serious adverse events (SAE). To be sure, serious adverse events are not just confined to clinical trials, but can occur following marketing approval as well.
AstraZeneca recently decided to pause clinical trials of Oxford University’s Covid-19 vaccine after a trial participant developed a serious adverse reaction. Media reports said the ailment was Transverse Myelitis, a serious condition involving inflammation of the spinal cord, which can cause muscle weakness, paralysis, pain and bladder problems. In rare instances, Transverse Myelitis can also be triggered by a vaccine.
AstraZeneca resumed the trial, following a review by UK drug regulator MHRA and an independent safety review committee, However, trials halted in India, Brazil, the US and South Africa are yet to resume.
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Frequently Asked Questions
A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.
There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.
Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.
The incident has opened up questions on the fate of the vaccine, and the reporting and compensation process to be followed if such an event were to occur.
What is a serious adverse event?
There are a number of reactions that can qualify as suspected serious adverse events, symptoms that require hospitalisation, life-threatening illness and even death. SAEs can be unexpected or serious, and causally related or result in death. But these are generally very rare. The general vaccine-induced side effects are mild and include soreness, swelling or redness at the injection site, and fever.
How is it reported?
The investigator should report all serious adverse reactions to the drug regulatory body, Drug Controller General of India (DCGI), sponsor of the trial and the concerned Ethics Committee (EC) that approved the trial protocol within 24 hours of occurrence. Further, the investigator should send a detailed report after due analysis to the DCGI, the EC Chairman, and the head of the institution where the trial is being conducted within 14 calendar days of the occurrence of SAE.
An Expert Committee appointed by the DCGI would examine the report of SAE and would give its recommendation to the regulator within 30 days. Based on the report, the DCGI will decide on the continuation of the trial.
Who compensates the participant?
According to the Indian Society for Clinical Research (ISCR) – the sponsor has an obligation to ensure that the affected participant receives full and appropriate treatment. The cost of such treatment is borne by the sponsor or reimbursed to the patient by the sponsor. In order that this provision is not misused, the opinion of the investigator and, if required, that of experts appointed by the Ethics Committee may be taken to determine whether the injury is trial-related or not. In case of death, their dependents are entitled to material compensation. Generally, DCGI will determine the cause of injury or death due to the SAE and make the final decision on the amount of compensation to be paid by the sponsor within 150 days of the occurrence.
The compressed timelines in the race to find a vaccine for a pandemic may not be big enough to reveal side effects that do not happen very often. For example, some side effects may only happen in 1 in 100,000 or 1 in 500,000 people. Also, vaccine trials may not have included groups who might have different types of side effects or who might have a higher risk of side effects than the volunteers who got the vaccine during clinical trials. Examples of these groups include people with chronic medical conditions and pregnant women. Post- marketing surveillance, therefore, assumes huge significance.
Have there been serious adverse events before?Many such adverse reactions have been reported, but the most grievous one was the 1966 respiratory syncytial virus (RSV) vaccine trial. RSV infects almost all children before they turn two, and causes flu-like symptoms. The vaccine didn't protect children and many infants still caught RSV, with worse symptoms than usual, requiring hospitalisation, and two toddlers died as a result. More recently, in December 2017, the Philippines had ordered the recall of a dengue vaccine after it was found to pose health risks in people not previously infected. The vaccine was recommended by the WHO to be used by people who had prior dengue infection. With robust reporting and pharmacovigilance systems, such adverse events can be reported beforehand with much lesser damage.