What conclusion should you make based on the data, should you reject or fail to reject the null hypothesis and what is the original claim?

7. Researchers conducted a phase 2 A B randomized controlled trial to determine the efficacy of NVX-Co V2372 COVID-19 Vaccine against B.1.351 Variant. The trial was conducted in South Africa, where participants were randomly assigned to receive two doses either of the NVX-Co V2372 vaccine or placebo. Participants received at least one injection of vaccine (n=2199) or placebo (n=2188). The primary efficacy end point was confirmed symptomatic Covid-19 that occurred within 7 days after receipt of the second injection. Among 2684 baseline seronegative participants, symptomatic Covid-19 was observed in 15 participants in the vaccine group and in 29 participants in the placebo group. These findings correspond to a vaccine efficacy of 49.4% (95% confidence interval [CI], 6.1 to 72.8)