List of global health threats for 2019 by World Health Organisation

• Nine out of ten people breathe polluted air every day. 

In 2019, air pollution is considered by WHO as the greatest environmental risk to health. Microscopic pollutants in the air can penetrate respiratory and circulatory systems, damaging the lungs, heart and brain, killing 7 million people prematurely every year from diseases such as cancer, stroke, heart and lung disease. 


Around 90% of these deaths are in low- and middle-income countries, with high volumes of emissions from industry, transport and agriculture, as well as dirty cookstoves and fuels in homes.  

The primary cause of air pollution (burning fossil fuels) is also a major contributor to climate change, which impacts people’s health in different ways. Between 2030 and 2050, climate change is expected to cause 250 000 additional deaths per year, from malnutrition, malaria, diarrhoea and heat stress. 

In October 2018, WHO held its first ever Global Conference on Air Pollution and Health in Geneva. Countries and organizations made more than 70 commitments to improve air quality. This year, the United Nations Climate Summit in September will aim to strengthen climate action and ambition worldwide. Even if all the commitments made by countries for the Paris Agreement are achieved, the world is still on a course to warm by more than 3°C this century. 

• Noncommunicable diseases, such as diabetes, cancer and heart disease, are collectively responsible for over 70% of all deaths worldwide, or 41 million people
• This includes 15 million people dying prematurely, aged between 30 and 69
• Over 85% of these premature deaths are in low- and middle-income countries.
• The rise of these diseases has been driven by five major risk factors: tobacco use, physical inactivity, the harmful use of alcohol, unhealthy diets and air pollution

The world will face another influenza pandemic – the only thing we don’t know is when it will hit and how severe it will be. Global defences are only as effective as the weakest link in any country’s health emergency preparedness and response system. 

• Resistance to tuberculosis drugs is a formidable obstacle to fighting a disease that causes around 10 million people to fall ill, and 1.6 million to die, every year
• In 2017, around 600 000 cases of tuberculosis were resistant to rifampicin – the most effective first-line drug – and 82% of these people had multidrug-resistant tuberculosis

The development of antibiotics, antivirals and antimalarials are some of modern medicine’s greatest successes. Now, time with these drugs is running out. Antimicrobial resistance – the ability of bacteria, parasites, viruses and fungi to resist these medicines – threatens to send us back to a time when we were unable to easily treat infections such as pneumonia, tuberculosis, gonorrhoea, and salmonellosis. The inability to prevent infections could seriously compromise surgery and procedures such as chemotherapy. 

In 2018, the Democratic Republic of the Congo saw two separate Ebola outbreaks, both of which spread to cities of more than 1 million people. One of the affected provinces  is also in an active conflict zone.

This shows that the context in which an epidemic of a high-threat pathogen like Ebola erupts is critical –  what happened in rural outbreaks in the past doesn’t always apply to densely populated urban areas or conflict-affected areas.

Primary health care is usually the first point of contact people have with their health care system, and ideally should provide comprehensive, affordable, community-based care throughout life. 

Primary health care can meet the majority of a person’s health needs of the course of their life. Health systems with strong primary health care are needed to achieve universal health coverage.

Vaccine hesitancy – the reluctance or refusal to vaccinate despite the availability of vaccines – threatens to reverse progress made in tackling vaccine-preventable diseases. Vaccination is one of the most cost-effective ways of avoiding disease – it currently prevents 2-3 million deaths a year, and a further 1.5 million could be avoided if global coverage of vaccinations improved. 

Measles, for example, has seen a 30% increase in cases globally. The reasons for this rise are complex, and not all of these cases are due to vaccine hesitancy. However, some countries that were close to eliminating the disease have seen a resurgence. 

Dengue, a mosquito-borne disease that causes flu-like symptoms and can be lethal and kill up to 20% of those with severe dengue, has been a growing threat for decades. 

An estimated 40% of the world is at risk of dengue fever, and there are around 390 million infections a year. 

A high number of cases occur in the rainy seasons of countries such as Bangladesh and India. Now, its season in these countries is lengthening significantly (in 2018, Bangladesh saw the highest number of deaths in almost two decades), and the disease is spreading to less tropical and more temperate countries such as Nepal, that have not traditionally seen the disease. 

The progress made against HIV has been enormous in terms of getting people tested, providing them with antiretrovirals (22 million are on treatment), and providing access to preventive measures such as a pre-exposure prophylaxis (PrEP, which is when people at risk of HIV take antiretrovirals to prevent infection). 

However, the epidemic continues to rage with nearly a million people every year dying of HIV/AIDS. Since the beginning of the epidemic, more than 70 million people have acquired the infection, and about 35 million people have died. Today, around 37 million worldwide live with HIV. Reaching people like sex workers, people in prison, men who have sex with men, or transgender people is hugely challenging. Often these groups are excluded from health services. A group increasingly affected by HIV are young girls and women (aged 15–24), who are particularly at high risk and account for 1 in 4 HIV infections in sub-Saharan Africa despite being only 10% of the population.