What can we learn from previous disease outbreaks?

Given that COVID-19 is only one of a series of emerging zoonoses, the experiences of the disease outbreaks in the past can inform strategies for the future.

Overall efforts to strengthen systems for prevention, detection and response to emerging infectious diseases in Asia have had mixed results. Significant investment has been made by development partners and developing countries following the epidemic of highly pathogenic avian influenza virus of type A and subtype H5N1 in 2004. Surveillance and diagnostic capacity have been built but HPAI remains endemic in key countries across much of Southeast Asia and in Egypt. Efforts to strengthen capacity in Africa to detect and manage pandemic threats have only just started and services lag behind Asia.

While few would argue against setting up programmes to respond to zoonotic outbreaks, there are concerns that, first, our responses may end up costing more than the diseases themselves, and, second, that these costs may be borne disproportionately by the world’s poorest people. During the bird flu pandemic, which started in 1997, there were several attempts to “restructure” the poultry industry, which in effect meant discouraging poor “backyard” poultry farmers, many of whom were women with few other ways to generate an income. A recent study in Egypt found that large-scale culling of poultry in response to an outbreak of bird flu (HPAI) was associated with an increase in childhood malnutrition.

Likewise, bans on wildlife trade, while sometimes successful, have in other cases led to unintended consequences, such as when a ban on polar bear products impoverished livelihoods in indigenous Arctic communities and reduced the communities’ tolerance for polar bears near their communities and participation in shared management initiatives. Response measures inappropriately targeting wildlife—such as poisoning or depopulation efforts—may threaten biodiversity and ecosystem services. These lessons reinforce the notion that interventions must weigh possible benefits with potential trade-offs; such an approach can help to optimize resource use and ensure equitable solutions.

While SARS appears to be eliminated, MERS continues to cause human deaths, because the virus still circulates in the intermediate host (dromedary species of camels). Vaccines were initiated for SARS but did not progress beyond phase-one human trials. Vaccines are currently under development for MERS but not yet approved.

A race is now on among the large private pharmaceutical companies, academic units and small biotech companies to develop a vaccine for COVID-19. More than 100 companies are involved in this work, but there remain real challenges, not only to develop an effective vaccine for this novel coronavirus, but also for quickly mass-producing it in sufficient quantities, and ensuring that it is available to all regardless of income, to protect every one alive on earth.