Researchers at the AIDS Institute, Department of Microbiology, and State Key Laboratory of Emerging Infectious Diseases at HKUMed, in collaboration with scientists at Tsinghua University and Columbia University, conducted a study on Syrian hamsters. They discovered that systemic human neutralising antibodies (HuNAb) or vaccines failed to fully prevent SARS-CoV-2 infection in the nasal turbinate of the hamsters. This finding reveals a mechanism underlying the difficulty of full protection against asymptomatic infection and highlights the importance of COVID-19 mucosal vaccine development.