Viruses dominate the WHO top 10 global health threats for 2019

 

A new year and a new group of virus-fighters to come up with innovative ideas to prevent protect us from severe virus infections. The World Health Organization (WHO) as recently presented a list of what they consider the top 10 major health threats for 2019.

Most viruses of the Viruskenner project made it on this list. The top 10 directly includes:

  1. Global influenza virus pandemic
  2. Ebola and other high-threat pathogens, including Zika, MERS-CoV and SARS
  3. Dengue
  4. HIV

However, I would like to argue that all points on this list will have an impact on severity of virus infections and spread in the population and are therefore important issues to address by virus-fighters.

The most obvious is vaccine hesitancy. This is a very important point because many (viral) diseases (including measles, polio, mumps, rubella, hepatitis A and B, and HPV) can be prevented with safe and effective vaccines. Furthermore, these vaccines provide indirect protection for those who cannot be vaccinated, via herd immunity (see previous blogs). Even if we develop safe and effective vaccines to protect against Ebola, Dengue and HIV, the effectiveness relies on the public support to get vaccinated to protect themselves and those around them. The major challenge is how to we stop the anti-vax era?

Weak primary health care. Many people in the world have no access to adequate primary health care services. Which is a serious problem for infectious diseases, as this is often the first contact people have with the health care system. A rapid and adequate diagnosis of HIV, novel influenza strains, Ebola and other high threat pathogens will lead to rapid treatment, education, quarantines and in case of Ebola safe burials. Rapid implication of these measures could prevent a local and even a global outbreak.

The remaining health threats from the WHO top 10 may be less obviously related to viral diseases but can still have a major impact on severity and spread.

Noncommunicable diseases are those diseases that cannot be directly transmitted from one person to another, for example cancer, diabetes mellitus, obesity and heart diseases. These diseases greatly increase one’s risk for being hospitalized with and dying from many viral infections, including seasonal influenza. Adopting a healthier life-style is therefore likely to improve our ability to combat severe infections.

Antibiotics are used to treat bacterial infections. So how will antibiotic resistance impact the outcome of viral infections? Many viral infections come with secondary bacterial infections that can be life threatening. For example, individuals with untreated HIV infections are more vulnerable for secondary bacterial infections (including tuberculosis), which are likely to kill if left untreated. The 1918 influenza pandemic killed more than 50 million people within one year. In a pre-antibiotic era, most of those individuals died as a result of a secondary bacterial infection in the lungs. Number of deaths due to bacterial co-infections during more recent influenza pandemics was likely reduced by the use of antibiotics. But what will happen if we run out of antibiotics during the next pandemic?

The next point on the list is a fragile and vulnerable setting, which includes lack of basic healthcare, drought, famine and conflicts. Viral infections are often more severe in areas where there is a famine. Although the underlying mechanisms are not fully understood, it is suggested that famine leads to suppression of the host’s immune response. Furthermore, both famine and conflicts (war) are likely to result in large groups of refugees. The conditions in which they live, close together, lack of basic hygiene, a weakened immune system and in absence of basic health care will make them especially vulnerable for severe infections.

Finally, one of the major threats on the WHO list, but maybe the least likely to be related to viral infections, is air pollution and climate change. Yet the consequences of climate change are likely to impact the spread and severity of viral infections. Climate change is more likely to result in crop failure, food shortages and famine, which will eventually lead to migration of climate refugees, which will increase the group of people living in fragile and vulnerable settings (see above). Furthermore, increasing temperatures enable tropical mosquitos to survive in regions of the world that used to be too cold, including Europe. Their presence will also bring the vector-borne diseases, including West-Nile virus, zika, dengue and chikungunya to these regions. In addition, climate change continues to affect bird migration patterns which could lead to spread of influenza to new locations and across a wider range of bird species, which challenges influenza surveillance.

So even if your goal is not to develop a new vaccine, there are other ways to fight viral infections. Whether it is by improving basic health care, preventing or adapting to climate change, developing new antibiotics, re-building peoples trust to vaccinate or just adopting a healthier lifestyle. Whatever your strategy is, an out-of-the-box approach might be the best way forward.

Factors that influence the severity and transmissibility of a pandemic influenza virus. Adapted from https://doi.org/10.3389/fcimb.2018.00343