Drone usage for medicine and vaccine delivery during the COVID-19 pandemic: attitude of health care workers in rural medical centres por Sham, Rohana, Ching, Sin Siau, Tan, Steven, Dawn, Chii Kiu, Sabhi, Hasminulhadi, Zhu Thew, Hui, Selvachandran, Ganeshsree, Shio, Gai Quek, Ahmad, Noorsiah, Mohd Ramli, Mohd Hanif