Covid-19: Looking ahead
The world is in the grip of the Covid-19 coronavirus pandemic. What advances have we made against the threat?
The emergence of the SARS - severe acute respiratory syndrome - virus from Hong Kong in 2003 gave the world a taste of how a novel coronavirus could infect a human population and rapidly develop into a major public health emergency. Thousands were infected and more than 10% of those who contracted the new agent died. But we learned rapidly how SARS was spreading and how it caused disease, which led to the development of effective control measures that stemmed the outbreak. Worryingly though, despite major effort, no effective vaccine for the infection was ever found, and no effective antiviral drugs were identified. This was compounded by the fact that, thanks to international action, the spread of the virus was halted and it ceased circulation and disappeared shortly afterwards. In 2012, a second novel coronavirus, MERS - middle eastern respiratory syndrome, emerged in Saudi Arabia. Lessons learned from SARS enabled control albeit over a more extended time period during which cases have been reported from 27 individual countries. But, again, there is no vaccine or effective antiviral treatment for MERS, which has a mortality rate of over 30%.
The current SARS-CoV-2 (Covid-19) infection emerged from China in December 2019 but spread much more rapidly than either SARS or MERS, reaching pandemic status in under 3 months. Eight months ago, the world had never heard of SARS-CoV-2 or Covid-19. Yet now, with the northern hemisphere apparently through the first wave of infection, cases are rising in the southern hemisphere and many are asking questions about the risk of second - and subsequent - waves of infection. Foremost among these are whether measures for control of the infection are adequate, or do they need revisiting? Can containment control the infection in the way that it did with SARS and MERS? How strictly must quarantine and basic infection control measures be applied? Will a vaccine be effective and when will it arrive?
Seventeen years after the emergence of SARS, technological advances in diagnosis of infection have rapidly enabled diagnostic tests to be produced for SARS-CoV-2 infection. Yet, despite the swift dissemination of these diagnostic procedures, there has been a marked difference in individual country’s successes in controlling the infection. If a second wave emerges, it will be important for best practices to be adopted worldwide. Among the new technologies applied in this pandemic has been the ability to achieve rapid whole genome sequencing of the virus. Mutations of the viral genome can result in greater, or conversely lower, virulence in a second wave of infection, and an open question at the moment is how rapidly is the virus mutating, and what will be the effects will these changes?
Greater understanding of the way in which the infection causes disease will be key to better treatment of affected individuals. Especially important is our understanding of the interaction between the virus and the host immune response. We are realising that much of the damage done by the infection in some patients appears to be caused by the immune system itself, meaning that immune modulation provides a potentially powerful way to alter the course of severe disease. In line with this thinking, broadly-acting immune modulators - like the steroid dexamethasone - have shown some, albeit limited effectiveness. Administration of convalescent plasma, or hyperimmune globulin, on the other hand, has not yet been shown to be of clear benefit. Antiviral chemotherapy similarly requires more detailed study. Controversial results have arisen with compounds such as hydroxychloroquine, and many of the antivirals tried so far have drawn a blank in terms of clinical effects. Nevertheless, despite the lack of success to develop a vaccine for either SARS or MERS, great hope is expressed for a vaccine against SARS-CoV-2. More than 150 vaccine projects have been iniatiated worldwide with unprecedented speed and ingenuity and many are already in clinical trials. Will vaccination work to prevent further waves of infection and stop the pandemic?
To address some of these questions, the European Society for Clinical Virology (ESCV) have organised a free of charge virtual meeting, which takes place on September 9th 2020 (ESCV 2020). New diagnostic procedures for this infection have been developed and deployed in this first wave of infection and the relative merits and challenges of these will be explored. Attempts will also be made to summarise what we have learnt so far about the nature of the virus, its genome and the immune response to infection. Rounding up with what are the prospects for its control and the experience with antivirals, immunomodulators and the promise of vaccines in control. Join clinical virologists from across the globe to hear current state of the data, informed opinion and front-line experience. This meeting will be an important review of where we are in the pandemic and how we move forward.