Towards a European strategy to address the COVID-19 pandemic

Many governments are looking for paths out of restrictive physical distancing measures imposed to control the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). With a potential vaccine against coronavirus disease 2019 (COVID-19) many months away, 1 one proposal that some governments have suggested, including Chile, Germany, Italy, the UK, and the USA, 2 is the use of immunity passports—ie, digital or physical documents that certify an individual has been infected and is purportedly immune to SARS-CoV-2. Individuals in possession of an immunity passport could be exempt from physical restrictions and could return to work, school, and daily life. However, immunity passports pose considerable scientific, practical, equitable, and legal challenges. On April 24, 2020, WHO highlighted current knowledge and technical limitations, advising “[t]here is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection…[a]t this point in the pandemic, there is not enough evidence about the effectiveness of antibody-mediated immunity to guarantee the accuracy of an ‘immunity passport’”. 3 In a follow-up tweet, WHO clarified that it is expected that infection with SARS-CoV-2 will result in some form of immunity. 4 Caution is warranted about how population level serology studies and individual tests are used. It is not yet established whether the presence of detectable antibodies to SARS-CoV-2 confers immunity to further infection in humans and, if so, what amount of antibody is needed for protection or how long any such immunity lasts. 3 Data from sufficiently representative serological studies will be important for understanding the proportion of a population that has been infected with SARS-CoV-2. These data might inform decisions to ease physical distancing restrictions at the community level, provided that they are used in combination with other public health approaches. 5 The use of seroprevalence data to inform policy making will depend on the accuracy and reliability of tests, particularly the number of false-positive and false-negative results, and requires further validation. 6 At the individual level, this reliability could have public health ramifications: a false-positive result might lead to an individual changing their behaviour despite still being susceptible to infection, potentially becoming infected, and unknowingly transmitting the virus to others. Individual-targeted policies predicated on antibody testing, such as immunity passports, are not only impractical given these current gaps in knowledge and technical limitations, but also pose considerable equitable and legal concerns, even if such limitations are rectified. Immunity passports would impose an artificial restriction on who can and cannot participate in social, civic, and economic activities and might create a perverse incentive for individuals to seek out infection, especially people who are unable to afford a period of workforce exclusion, compounding existing gender, race, ethnicity, and nationality inequities. 7 Such behaviour would pose a health risk not only to these individuals but also to the people they come into contact with. In countries without universal access to health care, those most incentivised to seek out infection might also be those unable or understandably hesitant to seek medical care due to cost and discriminatory access. 8 Such incentives must be understood in the context of the pressure governments might face from businesses seeking to adopt policies that return employees to the workforce, with corporate entities being the beneficiaries of the immunocapital of workers. 9 Furthermore, immunity passports risk alleviating the duty on governments to adopt policies that protect economic, housing, and health rights across society by providing an apparent quick fix. © 2020 Reuters/Andrew Kelly 2020 Since January 2020 Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre - including this research content - immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active. Like all such privileges administered by a government, immunity passports would be ripe for both corruption and implicit bias. Existing socioeconomic, racial, and ethnic inequities might be reflected in the administration of such certification, governing who can access antibody testing, who is front of the queue for certification, and the burden of the application process. By replicating existing inequities, use of immunity passports would exacerbate the harm inflicted by COVID-19 on already vulnerable populations. The potential discriminatory consequences of immunity passports might not be expressly addressed by existing legal regimes, because immunity from disease (or lack thereof) as a health status is a novel concept for legal protections, despite historical examples of the discriminatory impacts of immunoprivilege such as with yellow fever in New Orleans during the 19th century. 9 Depending on the jurisdiction, anti-discrimination laws might cover health status generally as a protected class, and also those for whom infection poses disproportionate risk—eg, older individuals, people who are pregnant, individuals with disabilities, or those with comorbidities. This inequity is not a consequence that can be legislated out of existence: adopting laws that prevent discrimination on the basis of immune status is incongruous with a process expressly intended to privilege socioeconomic participation according to such status. Under international human rights law, states have obligations to prevent discrimination, while also taking steps to progressively achieve the full realisation of social and economic rights. 10 Immunity passports would risk enshrining such discrimination in law and undermine the right to health of individuals and the population through the perverse incentives they create. When larger scale international travel recommences, countries might require travellers to provide evidence of immunity as a condition of entry. Under the International Health Regulations (2005) (IHR), states can implement health measures that “achieve the same or greater level of health protection than WHO recommendations”; however, such measures must have a health rationale, be non-discriminatory, consider the human rights of travellers, and not be more restrictive of international traffic than reasonably available alternatives. 11 Given current uncertainties about the accuracy and interpretation of individual serology testing, immunity passports are unlikely to satisfy this health rationale evidentiary burden 12 and are inconsistent with the WHO recommendations against interference with international travel that were issued when the WHO Director-General declared COVID-19 a Public Health Emergency of International Concern (PHEIC). 13 Given the discriminatory impact of immunity passports, any changes to WHO's recommendations should be considered in the context of the IHR's human rights protections. Immunity passports have been compared to international certificates of vaccination, such as the “Carte Jaune” for yellow fever. 14 However, there are significant differences between the two types of documents, occasioning fundamentally different burdens on individuals' health risk and bodily integrity, the public health risk, and an individual's capacity to consent and control. The main distinction between the two is the nature of the incentive. Vaccination certificates incentivise individuals to obtain vaccination against the virus, which is a social good. By contrast, immunity passports incentivise infection. Under the IHR, states can require travellers to provide vaccination certificates, but this is limited to specific diseases expressly listed in Annex 7, which currently only includes yellow fever, and if included in WHO recommendations, such as those issued following the declaration of a PHEIC as is the case for polio. 11 Once, and if, a vaccine is developed, COVID-19 vaccination certificates could be included in revised WHO recommendations for the COVID-19 PHEIC, while member states could consider requesting standing recommendations or revising the IHR's Annex 7 for the longer term. Until a COVID-19 vaccine is available, and accessible, which is not guaranteed, the way out of this crisis will be built on the established public health practices of testing, contact tracing, quarantine of contacts, and isolation of cases. The success of these practices is largely dependent on public trust, solidarity, and addressing—not entrenching—the inequities and injustices that contributed to this outbreak becoming a pandemic.

Without a cure, vaccine, or proven long-term immunity against SARS-CoV-2, test-trace-and-isolate (TTI) strategies present a promising tool to contain its spread. For any TTI strategy, however, mitigation is challenged by pre- and asymptomatic transmission, TTI-avoiders, and undetected spreaders, which strongly contribute to ”hidden" infection chains. Here, we study a semi-analytical model and identify two tipping points between controlled and uncontrolled spread: (1) the behavior-driven reproduction number \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${R}_{t}^{H}$$\end{document} R t H of the hidden chains becomes too large to be compensated by the TTI capabilities, and (2) the number of new infections exceeds the tracing capacity. Both trigger a self-accelerating spread. We investigate how these tipping points depend on challenges like limited cooperation, missing contacts, and imperfect isolation. Our results suggest that TTI alone is insufficient to contain an otherwise unhindered spread of SARS-CoV-2, implying that complementary measures like social distancing and improved hygiene remain necessary.

COVID-19 cases are very high across Europe. Current measures are not reducing virus spread sufficiently, and new SARS-CoV-2 variants are emerging. The B.1.1.7 and B1.351 variants, first identified in the UK and South Africa, respectively, have spread to many European countries.1, 2, 3, 4, 5 Although the biological properties of these variants are yet to be characterised, epidemiological data suggest they have a higher transmissibility than the original variant.6, 7 These viral properties could increase the effective reproduction number R in the population. In the case of B.1.1.7, estimates suggest R could increase from 1 to about 1.4 with no change in population behavior.3, 4 If true, many countries that have succeeded in reducing R to 1 or less will be confronted with a novel wave of viral spread despite the current measures.8, 9 Once a more contagious variant has established itself, stabilising the number of new infections will become increasingly difficult. Despite the availability of effective vaccines, production to meet demand and roll-out of vaccination programmes will take months. Countries will have to manage high case numbers and their adverse impact for several months to come. With slowly increasing population immunity and evolutionary selection pressure on the virus, the emergence of new SARS-CoV-2 variants will continue, potentially leading to more contagious variants, and perhaps even variants for which existing vaccines are less effective. Such variants could quickly exacerbate the crisis, long before enough people are vaccinated. While awaiting experimental data to understand the new variants, pan-European decisions have to be made, and actions have to be taken immediately to contain the spread of new variants. If measures are not taken to prevent the spread of novel variants with selective advantages, case numbers and hospital admissions will increase. A surge in cases could lead to the breakdown of health-care systems. In many countries, hospitals can no longer deliver care of the usual quality to all patients. Many intensive care units are already beyond capacity, and non-urgent procedures have been postponed for weeks or months. Delayed diagnosis and compromised care delivery for people with other diseases poses additional health risks, not just to patients with COVID-19, but for the whole population. Health-care professionals and other frontline workers have already been working under extreme conditions for most of the past year, and this has had a severe impact on their physical and mental health. If variants like B.1.1.7 lead to a new surge in cases, this could overwhelm health-care professionals and bring health-care systems to the breaking point. Ensuring that the burden on health care professionals is alleviated while safeguarding system sustainability is of critical importance. Adequate support for these crucial forces might require additional funds. Containment and mitigation become more challenging with the rise of a more infectious variant. Assuming that the B.1.1.7 variant does increase R from 1 to 1.4, then allowing it to spread without a change in population behaviour will mean case numbers double every week. Major efforts will be necessary to bring R back down to 1 or less and to regain control. Acting before B.1.1.7 has spread widely means that those same major efforts could strongly reduce the number of new cases and slow down the establishment of B.1.1.7. Europe needs to act now to delay and prevent any further spread of SARS-CoV-2,8, 9 particularly B.1.1.7, even in the absence of final experimental data. A clear plan for immediate pan-European action and rapid establishment of public health measures needs to be formulated since new variants with increased infectivity are likely to continue to arise. We suggest possible core measures in the panel . The guiding principle is to reduce case numbers as quickly as possible as this has strong advantages for health, society and economy. The joint action of all European countries will make each national and local effort more effective and impactful and safeguard public health across Europe. 8 Panel Core measures to prevent the spread of SARS-CoV-2 in Europe Achieve and maintain low case numbers with a clear prevention strategy • Define clear targets and rekindle motivation: clearly define the targets that need to be met for measures to be lifted and explain the rationale behind them; convincingly convey that the fight against the pandemic needs a collective effort that is in the interest of every citizen; and ensure adequate social and economic support for those in need. • Act early: implement mitigation measures before case numbers spike. • Reduce the number of physical contacts: meet as few different people as possible; implement and improve home-office and online schooling; small, stable social bubbles, and stable groups at home and at work should be preferred over alternating contacts. • Prevent contagion by individual measures such as physical distancing, hygiene, face masks, ventilation, and use of filters, avoiding closed and crowded spaces and staying at home when experiencing symptoms; provide FFP2 masks to those in need and to all who cannot work from home. Monitor the spreading of the virus and of individual variants • Test, trace, isolate, support: enforce mandatory isolation of people with confirmed infections and encourage preventive quarantine of suspected cases; support affected individuals and families. • Screen and test preventively: offer tests at schools and workplaces at no cost to detect outbreaks early and protect people; increase testing capacity to meet demand; use waste-water surveillance to detect local surges. • Increase genetic sequencing and PCR-based detection of the B.1.1.7 variant, as well as other variants of SARS-CoV-2. Stop the virus at borders and protect the vulnerable • Reduce travel within and across national borders, and require tests and quarantine for cross-border travelers; tests should be required 24h before travel and 7–10 days after travel; quarantine anyone arriving from countries with high local COVID-19 transmission or suspicious variants. • Improve the protection of, and support for, the elderly and vulnerable groups; foster European exchange about successful strategies and measures to speed up the progress. Increase the efficacy and pace of vaccination • Speed up vaccination: improve vaccine supply, delivery, and allocation by mutual learning and international cooperation; coordinate efforts to scale up the production of vaccines. • Monitor infections among vaccinated people to detect potential reinfection with new variants or deficient vaccination management as soon as possible. • Answer urgent questions through international cooperation; research ways to improve vaccination regimes to optimise logistics, or increase willingness to be vaccinated using data from multiple countries. Further details are available in the appendix. The longer restrictions last, and the less effective they become, the more depleted people's psychological, social, and economic resources become. Where novel variants require even stricter and longer measures than existing measures, it is of utmost importance to ensure that people with particularly heavy burdens receive financial and social support, that social burdens are justly distributed, and that mental health services meet the increasing demand to cope with bereavement, isolation, loss of income, fear, alcohol and drug misuse, insomnia, and anxiety as a result of the pandemic and lockdown strategies. Contextual factors, and factors affecting risk behaviour such as risk perception, must also be considered. The core principles of action are to avoid importing new variants, to prevent their spread, and to improve molecular surveillance. The earlier and more effectively countries act, the earlier the restrictions can be relaxed. All types of measures ought to be coordinated and synchronised across Europe. Every additional reduction of contagion (ie, of R) counts, as it reduces the necessary duration of strict measures more than proportionally.