The long road of pandemic vaccine development to rollout: A systematic review on the lessons learnt from the 2009 H1N1 influenza pandemic

BACKGROUND: The 2009 Influenza A(H1N1) pandemic prompted one of the largest public health responses in history. The continuous emergence of new and deadly pathogens has highlighted the need to reflect upon past experiences to improve pandemic preparedness. The aim of this study was to examine the development and rollout of 2009 influenza A(H1N1) pandemic vaccine and knowledge challenges for the effective implementation of vaccination programs for COVID-19 and future influenza pandemics. METHODS: A systematic review was conducted searching EMBASE (inception to current date) and PUBMED (from January 2009 to current date) databases for relevant published studies about influenza A(H1N1) pandemic vaccines. A Google search was conducted to identify relevant documents from gray literature. Selected Studies were reviewed and summarized. RESULTS: A total of 22, comprising of 12 original studies and 10 relevant documents met the inclusion criteria. Fourteen papers reported an initial high demand that outweighed production capacity and caused vaccine shortages. Vaccine procurement and supply were skewed toward high-income countries. Low vaccination rates of about 5%-50% were reported in all studies mainly due to a low-risk perception of getting infected, safety concerns, and the fear of adverse effects. CONCLUSIONS: Safety concerns about the approved H1N1 vaccines resulted in many unsuccessful vaccination campaigns worldwide. Understanding the factors that influence people's decision to accept or refuse vaccination, effective risk communication strategies, adequate resources for vaccine deployment initiatives and building local capacities through shared knowledge and technology transfer may help to improve COVID-19 vaccine uptake and accelerate pandemic control.