COVID-19 vaccine effectiveness and variants in Nepal: study protocol for a test-negative case-control study with SARS-CoV-2 genetic sequencing by Bijukchhe, SM, O'Reilly, PJ, Theiss-Nyland, K, Gurung, M, Pokhrel, B, Kelly, S, Acharya, S, Maharjan, S, Shrestha, A, Pandey, B, Lama, M, Shrestha, I, Voysey, M, Eordogh, A, Shrestha, S, Feng, ES, Li, G, Shah, G, Pollard, AJ, Shrestha, S