The unknown: will we defeat global epidemics ?

Remarks given at the conference ‘The unknown, 100 years from now: A voyage of discovery’ , Lisbon, Portugal, 4-5 December 2015

Dear colleagues, Ladies and gentlemen,

Thank you. I feel truly honored by your invitation to speak today.

My remarks will focus on the question of whether the world can bring an end to epidemics a hundred years from now. I see at least two issues to be considered under this broader question.

The first is: will the world end the current major epidemics that it is facing, namely, HIV/AIDS, TB, malaria?

And the other: will the world, a hundred years from now, end the risk of emergence or re emergence of epidemics?

To the first question, my answer would be a cautious yes.

Yes, because the progress made in the fight against these epidemics in the last fifteen years has been just remarkable – with no precedent in the history of public health – and undoubtedly, a source of major hope for the future. The “end” of AIDS and TB that was unthinkable just fifteen years ago, has now not only entered the language of scientists but has been endorsed as an objective that the world set to itself for 2030 under the new Sustainable Development Agenda adopted by the UN last September.

Progress has been amazing and amazingly fast.

The number of people accessing antiretroviral treatment has increased from 200 000 in 2000 to 16 million by now. The number of new HIV infections has decreased by 40% and AIDS-related deaths have decreased by 35 % globally in the last five years. New effective medicines with fewer adverse effects and/or that are capable of overcoming emerging viral resistance are becoming available every year. The life expectancy of an HIV-infected person on effective AIDS treatment is now similar to that of an HIV-negative person.

We have witnessed a 50% fall in mortality from tuberculosis since 1990, with most of that improvement taking place since 2000. Effective diagnosis and treatment of TB will have saved an estimated 43 million lives between 2000 and 2014.

We have learned about the ingredients of success: political commitment, community mobilization and involvement, resources, innovative approaches to delivery of care, to the international intellectual property framework, to development assistance, and to the global governance of health.

Importantly, science has been vital in advancing control and treatment of the diseases: new scientific evidence, products and approaches have rapidly been incorporated into programs; and the scientific community has been intimately involved in strategy development, implementation and assessment of the response to the epidemics.

I am confident that science will further generate efficacious new medicines, possibly leading to eradication of the virus from infected individuals – that is a cure for AIDS -, and also, most likely, effective vaccines to prevent infection with HIV and transmission of TB.

If my “yes” to the question of whether we will end today’s major pandemics is cautious, it is not because of limitations that I would foresee to progress in science. It is because ending AIDS and TB is not just about fully understanding transmissibility, pathogenicity and immune responses, and generating new medicines and vaccines. It is about our ability in the future to address the social, structural and political determinants that underlie the emergence and expansion of these diseases.

Despite the progress, two million people still become infected with HIV every year and TB now ranks along with HIV as a leading cause of death with a worldwide death toll of 1.2 million.

Epidemics have always been powerful indicators of social and economic inequities, structural weaknesses of health and social systems, and of failures to address the transnational nature of health.

In contrast with the progress made globally, only minor and sometimes little progress has been made with the so-called “concentrated” epidemics of HIV among vulnerable groups of the population. Of the 500 000 new cases of multi-drug resistant TB that primarily affect vulnerable populations, only a quarter are detected and reported.

By vulnerability I refer to young women in sub-Saharan Africa that have no control over their sexual life, men having sex with men, people who inject drugs, sex workers and incarcerated people, in most parts of the world. HIV remains highly prevalent in these communities in both developed and developing countries, and access to prevention and treatment for vulnerable and marginalized groups remains disproportionally low. A strong emphasis – if not an over-reliance – on biomedical approaches has led to an inadequate public health focus on fighting stigma, discrimination, and inappropriate legal and policy environments, as well as an insufficient focus on social and political determinants of health: just think of the major negative impact on the prevention of the transmission of HIV that the denial of the viral origin of AIDS by a former South African president had in a country that is still paying for this absurdity with one of the highest HIV sero-prevalence rates in the world. Together with Fernando Henrique Cardoso, Jorge Sampaio and our fellow members of the Global Commission on Drug Policy, we are denouncing the focus on repressive drug policies that emphasize prohibition and law enforcement rather than public health, approaches that continue to fuel the HIV and hepatitis epidemics among people who inject drugs.

Another source of caution about the prospect of ending these epidemics is the development of resistance, now a major challenge for the prevention and treatment of TB. Resistance may arise from improper treatment regimens and TB programs failing to ensure that patients complete the whole course of treatment. Globally, MDR TB represents 3.3 % of new TB cases and 20 % of previously treated patients that come for re-treatment, but these figures reach 30 and 70 % in some countries of Eastern Europe. Of the few patients with MDR TB who access treatment, only 50% have a successful outcome.

The recent Ebola outbreak probably best illustrates how much health systems and access to basic care are essential in the control of epidemics and cannot be compensated by measures such as confinement and border closure. In the absence of an effective treatment against the Ebola virus, recovery relies on access to rehydration and basic care measures. Whereas the mortality from Ebola has been over 50% in affected countries in West Africa, it is estimated that it would have been less than 10% under the conditions of functioning health systems in developed countries. Similar considerations would apply to cholera or dengue outbreaks.

At the time of the Ebola outbreak, Liberia had less than 50 doctors for a population of more than 4 million. International development assistance has too long neglected structural factors and investing in building sustainable health systems because of a dominant technical vision of international health programs centered on medicines and vertical interventions that neglect social and structural contexts.

Answering the question of whether we will end AIDS and TB by 2030 or even 2115 also involves asking whether the world will be able to reduce social and economic inequities. The question is legitimate as we see increasing gaps between the rich and the poor within countries and across the world, and particularly in the many countries that are now transitioning from low income to a middle-income status, and in the large emerging economies.

Let us hope that – just as in XIX century Europe – political and societal changes will help to accelerate sanitary and social reforms and economic growth that will allow us to end HIV/ AIDS, TB and Ebola at the global level.

Even with these qualifications, my answer is yes. I do foresee an end to AIDS and TB, at least as global public health threats well before of a hundred yeas from now, and consider this as an attainable objective for 2030. It is much harder however to foresee complete elimination of the diseases (that is, zero incidence) or eradication, which means disappearance of both the disease and its causal agent.   So will need to remain vigilant for many years once control has been achieved.

To the second question of whether the next hundred years will see a world free of emerging or re-emerging epidemics, answer must be no.

Bacteria, viruses and parasites that may cause transmissible diseases co-exist with humans and will obviously continue to do so. The microbial world is capable of remarkable mutation, evolution, and adaptation to the environment. Microbes are in the environment and in animals but humans themselves are also a reservoir of bacteria, some being beneficial and some potentially pathogenic.

Eradication of infectious diseases and a world free of epidemics has long been an idealistic goal. From the XIVth century, ports have set quarantine measures. Constantinople, Tangiers and Alexandria put together sanitary councils to protect the population from cholera arriving from the Indies?, and the first international sanitary regulations were developed as early as the 1860s.

However, infectious diseases will never disappear, as first predicted by Charles Nicolle, Director of the Pasteur Institute in Tunis and Nobel laureate in medicine in 1928, in his book “Naissance, vie et mort des maladies infectieuses”.

Moreover global warming, the growth of transport and communications, the increase in the world population, the intensification of livestock farming, increasing contacts between humans and wild fauna, the thoughtless use of antibiotics in human and veterinary medicine, all point to the future emergence and re-emergence of epidemics.

The close interaction between people and pigs, and chicken and ducks led to the recent flu epidemics in Asia. Intense cultivation of fruit trees for pork farming has led to the proliferation of fruit bats, vectors of the Nipah virus, the agent of the respiratory syndrome outbreaks in Asia in 2011.

Eradication of small pox in 1978 will likely remain as the only example of eradication of an infectious disease through vaccination. There are several reasons for this: humans are the only reservoir of the disease and the disease is always symptomatic, with no silent carriers of the infection.

In the other diseases for which we have effective vaccines, the goal is elimination rather than eradication: diphteria, tetanus, poliomyelitis, whooping cough. Any loosening in vaccine coverage is immediately followed by re-emergence of the disease, as recently seen for measles in Europe and in the US.

In the case of new epidemics and diseases for which no vaccine is yet available, the emerging strategic model for control consists of a combination of several interventions: an early diagnosis using rapid bedside diagnostic tests; mathematical modelling of the early stages of the development of the epidemic, sensible public health measures including well thought-out confinement, and treatment interventions even if imperfect, to decrease transmission and disrupt the epidemic chain.

In addition, good governance, education, training of health care personnel and communities, economic growth that reduces social and economic inequities, will all be essential in controlling infectious risks.

Thus, epidemics in the future will persist, as predicted by Charles Nicolle. But epidemics will be better anticipated, detected and contained.

This will especially be true if we apply the lesson from HIV and TB: that epidemics can be reversed when we address them not only with the tools of public health, but also with human rights and efforts to achieve social and economic justice.