India is rapidly emerging as a focal point in the global race to develop a safe and effective vaccine against chikungunya, a mosquito-borne viral illness that has long eluded reliable preventive protection. With Zydus Life Sciences now pushing forward with its candidate and joining Bharat Biotech and the Serum Institute of India in the vaccine development landscape, the momentum for indigenous solutions has accelerated. While Bharat Biotech already leads with late-stage clinical trials, the entry of Zydus highlights both the opportunities and challenges facing Indian vaccine developers as regulators demand more robust safety and immunogenicity data before moving ahead. This unfolding scenario underlines not only India’s scientific capabilities but also the complexity of bringing a new vaccine against an unpredictable virus into the hands of millions at risk.
The chikungunya virus, belonging to the Alphavirus genus, spreads primarily through Aedes mosquitoes such as Aedes aegypti and Aedes albopictus. Known for causing high fever, severe joint pain, rash, and fatigue, the illness has historically surged in periodic outbreaks across Asia, Africa, and the Americas. Unlike other mosquito-borne diseases such as dengue, chikungunya’s joint pain can linger for months, severely impacting quality of life. According to the European Centre for Disease Prevention and Control, more than 6,20,000 cases and 213 deaths were reported worldwide in 2024, underscoring the urgency of vaccine development. While prevention relies mainly on mosquito control and personal protection, the absence of an effective vaccine has left public health systems vulnerable.
Zydus enters the vaccine race with early trials
Zydus Life Sciences has recently presented its proposal for an inactivated chikungunya vaccine to India’s apex regulatory body, the Subject Expert Committee on vaccines. The company has completed acute and repeat-dose toxicity studies in animal models to determine the safe starting dose for humans. However, the committee, after a detailed review, found gaps in the data package and asked the company to revise its Phase I protocol before seeking approval for human trials. Specifically, the regulators noted the absence of immunogenicity data to support the protective dose, the lack of a lethal dose challenge study in non-human primates, and the absence of a Developmental and Reproductive Toxicology study.
These omissions are significant because vaccine development is not only about demonstrating safety but also proving that the candidate induces a robust and durable immune response. Without confirming immunogenicity and protective dosing criteria, advancing into human testing carries risks. The SEC’s insistence on stronger data reflects a careful approach in safeguarding participants while ensuring that India’s vaccine pipeline remains scientifically rigorous. Zydus had proposed a combined Phase I/II trial design that would explore one-dose or two-dose regimens depending on Phase I results. But the committee advised that these phases be conducted separately, stressing the need to first establish the safety and tolerability of the vaccine before exploring immunogenicity in a larger group.
For Zydus, this regulatory pushback means delays in beginning its human trials. Yet, it also reflects the high bar set by Indian authorities in vaccine approval, particularly in the aftermath of the Covid-19 pandemic when the country witnessed both the importance of speed and the imperative of safety. The company’s reliance on the parent strain of the chikungunya virus may offer advantages in terms of broad immune protection, but until the pre-clinical data is fortified, its candidate cannot move into the critical human testing phase.
Bharat Biotech and global parallels in chikungunya vaccines
While Zydus prepares to resubmit its protocol, Bharat Biotech continues to maintain its frontrunner status with its candidate BBV87. Developed in collaboration with the International Vaccine Institute and CEPI, Bharat Biotech’s vaccine has already advanced to Phase III trials after encouraging results in earlier stages. CEPI, launched in 2017 at Davos, has been a pivotal global partnership driving vaccine preparedness against emerging diseases. Its involvement in Bharat Biotech’s project underscores international confidence in India’s ability to produce a viable vaccine for a disease that has plagued communities for decades.
The Phase II trials of BBV87 reportedly demonstrated promising immunogenicity, paving the way for late-stage testing across larger populations. Bharat Biotech’s track record, particularly during the Covid-19 pandemic when it developed Covaxin, strengthens its credibility as a leader in indigenous vaccine development. If successful, BBV87 could become India’s first approved chikungunya vaccine, offering both national protection and export opportunities in countries vulnerable to outbreaks.
Globally, progress has already been made. French biotechnology company Valneva secured US approval in 2023 for its live-attenuated chikungunya vaccine IXCHIQ, the first of its kind to reach the market. Bavarian Nordic followed with VIMKUNYA, a virus-like particle vaccine cleared for adolescents and adults. Valneva has also partnered with the Serum Institute of India, enabling regional manufacturing and potential imports to meet demand in South Asia. This partnership highlights India’s central role not only as a vaccine innovator but also as a manufacturing hub for global supplies.
For the Serum Institute, already the world’s largest vaccine manufacturer, its involvement in chikungunya vaccine production is a natural extension of its role in global immunization programs. While SII has yet to present an indigenous candidate, its collaboration with Valneva ensures that India will not be left out of global access to already-approved vaccines. This dual approach—local innovation from Bharat Biotech and Zydus alongside global manufacturing tie-ups through SII—places India in a unique position in the chikungunya vaccine race.
The global landscape makes it clear that chikungunya vaccines are moving from concept to reality. Yet, for India, the challenge is twofold: ensuring that its candidates meet the highest standards of safety and efficacy while also securing timely approvals that prevent dependency on imports. With outbreaks becoming more frequent and widespread, the urgency of developing a domestic vaccine cannot be overstated.
