For all of the varied work on COVID-19 vaccine candidates, the majority of vaccines to win emergency use authorization have fallen into a handful of categories, including mRNA, viral vector and inactivated vaccines.

Zydus Cadila (NSE: CADILAHC) is adding more diversity to the pool with its ZyCoV-D vaccine, which recently received emergency use authorization (EUA) in India. The vaccine will be available for people 12 and older.

Healthcare workers can administer the plasmid DNA vaccine with a needle-free applicator. Zydus is using the PharmaJet (Golden, Colo.) Tropis needle-free injection system for this purpose. Zydus claims that the needle-free system can reduce side effects.

The PharmaJet Tropus needle-free delivery system.

The vaccine is also unique in that it requires three doses rather than one or two. The last two doses are administered 28 and 56 days after the first.

The need for three doses could “affect its overall penetration,” said Prashant Khadayate, pharma analyst at GlobalData.

Ahmedabad, India–based Zydus plans to seek authorization for a two-dose regimen of the vaccine.

In a Phase 3 interim analysis, the vaccine was 66.6% effective in a studying involving 28,000 volunteers. It was 100% effective against moderate to severe disease. The interim efficacy trailed that of other available COVID-19 vaccines, including Covaxin, the first indigenous vaccine to win an EUA in India.

The plasmid DNA platform has advantages in terms of manufacturability and, unlike viral vector vaccines, does not lead to vector-based immunity.

The company aims to produce between 100 and 120 million doses of the vaccine annually.