Four more Covid-19 vaccines are in the pipeline and their manufacturers may approach the drug controller for emergency use authorisation, the Health Ministry said on Tuesday. Union Health Secretary Rajesh Bhushan said Zydus Cadila, Sputnik V, Biological E and Gennova are other vaccines which are in advanced clinical trials in India. The govt said, Zydus Cadilla completed Phase 2 clinical trials of its vaccine in December of last year and has been granted approval for Phase 3. Similarly, Phase 2 clinical trials of Russia's Sputnik-V vaccine have also concluded and Phase 3 trials are underway. For Biological E, Bhushan said the Phase 1 clinical trials of its vaccine started in December and Phase 2 is expected to begin in March. Gennova's Covid-19 vaccine is currently in Phase 1 with Phase 2 clinical trials likely to begin in March this year.