Is long COVID the next global health crisis?

The rapid development and deployment of coronavirus disease 2019 (COVID-19) vaccines should be heralded as a feat of true scientific collaboration that saved millions of lives [1]. Despite the success, vaccines do not offer complete protection against infection, mild, and severe disease [2-5] and the development of a long-term complex symptom profile, commonly referred to as long COVID [5,6]. Long COVID results from a positive infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19. It used ribonucleic acid (RNA), which is prone to replication and proliferation, leading to the transmission of variants that are a threat to global health. SARS-CoV-2 is known to evolve at an approximate rate of 1.1 × 10 -3 substitutions per site per year, equivalent to a single substitution every 11 days [7]. Whilst not all mutations pose a threat to public and global health, previous variants including Omicron (B.1.1.529, BA.1, BA.1.1, BA.2, BA.3, BA.4, and BA.5 lineages) and Delta (B.1.617.2 and AY lineages) are widely regarded as variants of concern [8]. Data highlights that there is no difference in risk level between Delta and Omicron BA.1 variant among those that are triple-vaccinated [9]. These variants are characterised by several mutations that affect the spike protein and increase transmissibility [10], leading to the sustained and widespread transmission of acute infection which will inevitably result in increased progression of long COVID.