How a vaccine is tested and approved in India
When a vaccine is described as approved in India, what has actually been checked, and who has given permission? The answer involves several decisions: whether human testing may begin, whether participants are protected, what the evidence shows, and whether the product may be manufactured or imported for sale. Each stage answers a different question.
Who makes the decisions?
The Central Drugs Standard Control Organization, or CDSCO, is India's central drug authority. Its headquarters handles approval of new drugs and clinical trials. The New Drugs and Clinical Trials Rules, 2019 name the Drugs Controller, India, commonly referred to as the Drugs Controller General (India), or DCGI, as the Central Licencing Authority.
CDSCO and DCGI are connected parts of the regulatory system. With prior Central Government approval, the Rules allow qualifying CDSCO officers to take on delegated powers. Decisions can therefore be shared across these officers.
Notified on 19 March 2019, the Rules cover new drugs, clinical trials and ethics committees, among other matters. Vaccines remain within their legal definition of a new drug, even beyond the four-year limit that applies to some other drugs. Here, “new” describes a regulatory category rather than when a vaccine was invented.
Before human testing
The Rules require sufficient evidence from nonclinical studies or earlier clinical trials to support safety for a proposed human trial. For first-in-human studies, the starting dose must be calculated carefully from nonclinical pharmacological and toxicological data. This evidence helps decide whether a trial can begin. Protection against disease still needs to be established.
Nonclinical testing includes methods beyond animal testing. A 2023 amendment explicitly listed cell-based assays, organ chips and micro physiological systems, sophisticated computer modelling, other human biology-based methods, and animal studies. Animal studies remain part of the list; this does not mean every animal test can be replaced.
What the trial phases ask
Phase I begins human testing with an emphasis on safety and tolerability: an initial assessment of how people tolerate the product being tested. Protection against disease and the possibility of rare harms remain open questions at this stage.
For vaccines, Phase II examines immunogenicity, meaning the immune response. ICMR's account of vaccine development, published by the Health Ministry, identifies this as a Phase II task. The Rules also describe choosing the dose and regimen for Phase III as an important goal. An immune response alone is insufficient proof of protection against disease.
Phase III aims to confirm the early evidence for the proposed use and intended population. This provides a basis for a marketing decision. It may also explore use in wider populations. Permission to sell remains a separate step, and some rare or long-term adverse effects may go undetected.
Each phase has a purpose, but its size can vary. The Rules tie participant numbers to the nature and aim of a trial. They allow appropriate comparisons with placebo, no treatment, active controls or different doses. The comparison used and the number of participants therefore depend on the trial.
Permission, oversight and consent
Regulatory trial permission and ethics approval are separate requirements. A registered ethics committee must approve the trial protocol and oversee the trial throughout.
The trial must also be registered with the clinical trial registry maintained by the Indian Council of Medical Research, or ICMR, before the first participant is enrolled. Registration puts the study on a public record. ICMR maintains the registry; the regulator grants approval. Permission to market the vaccine is a separate matter.
Informed consent requires participants to receive information they can understand and give their written agreement freely. Consent materials must explain that participation is voluntary and that a participant may withdraw without losing benefits otherwise due. These requirements matter throughout the research process, alongside regulatory permission and ethics oversight.
What happens when someone is harmed?
An adverse event is an unwanted medical occurrence during treatment or a trial. Recording it tells us what happened; assessing its cause is a separate task. The term alone leaves that cause open.
Investigators must report serious adverse events within 24 hours of occurrence to the Central Licencing Authority, the sponsor or its representative, and the ethics committee that approved the study. A late report must explain the delay. This duty applies even while the cause is being investigated.
If a participant is injured during a trial, the sponsor must provide free medical management for as long as the investigator considers necessary, or until the injury is established to be unrelated to the trial, whichever is earlier. The participant need not prove the cause before receiving care. Trial-related injury or death also requires financial compensation under the prescribed procedure. Medical management and compensation are separate obligations.
From trial evidence to permission to sell
Commercial sale needs permission separate from permission to conduct research. The Rules provide a separate route for seeking permission to import or manufacture a new drug for sale or distribution. Favourable trial results inform that decision.
Product quality is also assessed. The marketing application must include the quality-control testing protocol, impurity profile and release specifications. After obtaining new-drug permission, a manufacturer must also apply for a manufacturing licence under the Drugs and Cosmetics Rules, 1945. Clinical evidence and manufacturing requirements both matter.
The Rules also provide an accelerated-approval route for specified circumstances. This can use a surrogate endpoint: a measure reasonably likely to predict clinical benefit. Post-marketing trials must then validate the expected benefit. This route has conditions and evidence requirements. It is one route among others, and the usual sequence of phases allows exceptions.
Why monitoring continues after approval
Broader use can reveal events too rare to appear in clinical trials. The Rules therefore require close monitoring after marketing and a fresh assessment of the product's balance of benefits and risks. Some risk remains after approval, which is why monitoring continues.
Phase IV trials take place after approval and concern approved uses. They can investigate additional safety questions and aspects of use left unresolved before approval. They are one form of further study within the wider work of post-marketing surveillance.
Manufacturers retain reporting responsibilities, including periodic safety update reports and reports of serious unexpected adverse reactions to the regulator. They must follow regulatory action arising from review. Permission to sell comes with these continuing responsibilities.
How to read an approval claim
Ask what the announcement actually concerns: permission to start a trial, evidence from a particular phase, or permission for sale. Then ask which question the evidence answers. An immune-response result, a reported adverse event and a regulatory decision each mean something different. These distinctions help you assess vaccine news and place each announcement in the wider approval process.
To explore scientific concepts through changing inputs and observing responses, visit Learnacy Labs. Its browser-based interactive experiments span subjects including biology, chemistry and physics.