Adolescence is the phase of life between childhood and adulthood, from ages 10 to 19. It is a unique stage of human development and an important time for laying the foundations of good health. Adolescents experience rapid physical, cognitive and psychosocial growth. This affects how they feel, think, make decisions, and interact with the world around them.

In almost every country, the proportion of people aged over 60 years is growing faster than any other age group, as a result of both longer life expectancy and declining fertility rates. This population ageing can be seen as a success story for public health policies and for socioeconomic development, but it also challenges society to adapt, in order to maximize the health and functional capacity of older people as well as their social participation and security.

Air pollution is contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere. Household combustion devices, motor vehicles, industrial facilities and forest fires are common sources of air pollution. Pollutants of major public health concern include particulate matter, carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide. Outdoor and indoor air pollution cause respiratory and other diseases, which can be fatal.

Antimicrobial resistance (AMR) happens when microorganisms (such as bacteria, fungi, viruses, and parasites) change when they are exposed to antimicrobial drugs (such as antibiotics, antifungals, antivirals, antimalarials, and anthelmintics). Microorganisms that develop AMR are sometimes referred to as “superbugs”. As a result, the medicines become ineffective and infections persist in the body, increasing the risk of spread to others. AMR occurs naturally over time, usually through genetic changes. However, the misuse and overuse of antimicrobials is accelerating this process.

Blindness is the inability to see. The leading causes of chronic blindness include cataract, glaucoma, age-related macular degeneration, corneal opacities, diabetic retinopathy, trachoma, and eye conditions in children (e.g. caused by vitamin A deficiency). Age-related blindness is increasing throughout the world, as is blindness due to uncontrolled diabetes. On the other hand, blindness caused by infection is decreasing, as a result of public health action. Three-quarters of all blindness can be prevented or treated.

Blood safety encompasses actions aimed at ensuring that everyone has access to blood and blood products that are as safe as possible, available at reasonable cost, adequate to meet the needs of patients, transfused only when necessary, and provided as part of a sustainable blood programme within the existing health care system.

Breastfeeding is the normal way of providing young infants with the nutrients they need for healthy growth and development. Virtually all mothers can breastfeed, provided they have accurate information, and the support of their family, the health care system and society at large. Colostrum, the yellowish, sticky breast milk produced at the end of pregnancy, is recommended by WHO as the perfect food for the newborn, and feeding should be initiated within the first hour after birth. Exclusive breastfeeding is recommended up to 6 months of age, with continued breastfeeding along with appropriate complementary foods up to two years of age or beyond.

Cancer is the uncontrolled growth and spread of cells. It can affect almost any part of the body. The growths often invade surrounding tissue and can metastasize to distant sites. Many cancers can be prevented by avoiding exposure to common risk factors, such as tobacco smoke. In addition, a significant proportion of cancers can be cured, by surgery, radiotherapy or chemotherapy, especially if they are detected early.

Cardiovascular diseases (CVDs) are disorders of the heart and blood vessels and include coronary heart disease, cerebrovascular disease, rheumatic heart disease and other conditions. Four out of five CVD deaths are due to heart attacks and strokes. Individuals at risk of CVD may demonstrate raised blood pressure, glucose, and lipids as well as overweight and obesity. These can all be easily measured in primary care facilities. Identifying those at highest risk of CVDs and ensuring they receive appropriate treatment can prevent premature deaths. Access to essential NCD medicines and basic health technologies in all primary health care facilities is essential to ensure that those in need receive treatment and counselling.

Protecting and improving the health of children is of fundamental importance. Over the past several decades, we have seen dramatic progress in improving the health and reducing the mortality rate of young children. Among other encouraging statistics, the number of children dying before the age of 5 was halved from 2000 to 2017, and more mothers and children are surviving today than ever before. However, a great deal of work remains to further improve the health outcomes for children. The world is facing a double mandate. More than half of child deaths are due to conditions that could be easily prevented or treated given access to health care and improvements to their quality of life. At the same time, children must also be given a stable environment in which to thrive, including good health and nutrition, protection from threats and access to opportunities to learn and grow. Investing in children is one of the most important things a society can do to build a better future.

The resulting changes in the global climate bring a range of risks to health, from deaths in extreme high temperatures to changing patterns of infectious diseases. Climate and weather variables pose threats to food and water security, and cause outbreaks of waterborne and vectorborne diseases. Moreover, the increased pressure on scarce resources triggers climate-related migration and conflicts. Under business-as-usual scenarios, it is estimated that between 2030 to 2050, climate change will cause an additional 250 000 deaths annually.

Coronavirus disease (COVID-19) is an infectious disease caused by the SARS-CoV-2 virus.

Most people infected with the virus will experience mild to moderate respiratory illness and recover without requiring special treatment. However, some will become seriously ill and require medical attention. Older people and those with underlying medical conditions like cardiovascular disease, diabetes, chronic respiratory disease, or cancer are more likely to develop serious illness. Anyone can get sick with COVID-19 and become seriously ill or die at any age. 

Dengue (break-bone fever) is a viral infection caused by the dengue virus (DENV), transmitted to humans through the bite of infected mosquitoes. It is more common in tropical and subtropical climates worldwide, mostly in urban and semi-urban areas.

Diabetes is a chronic, metabolic disease characterized by elevated levels of blood glucose (or blood sugar), which leads over time to serious damage to the heart, blood vessels, eyes, kidneys, and nerves. The most common is type 2 diabetes, usually in adults, which occurs when the body becomes resistant to insulin or doesn't make enough insulin. In the past three decades the prevalence of type 2 diabetes has risen dramatically in countries of all income levels. Type 1 diabetes, once known as juvenile diabetes or insulin-dependent diabetes, is a chronic condition in which the pancreas produces little or no insulin by itself.

Diagnostic imaging is the use of X-ray, ultrasound, radioactive isotopes, or magnetic resonance to produce a visual display or representation of structural and / or functional information of the "inside" of the human body. Diagnostic imaging, especially X-ray based examinations and ultrasonography, is crucial in every medical setting and at all levels of heath care. Though clinical judgment maybe sufficient in treating many conditions, the use of diagnostic imaging services is paramount in confirming, correctly assessing and documenting disease processes and also in judging the disease response to treatment.

Rehabilitation of people with disabilities is a process aimed at enabling them to reach and maintain their optimal physical, sensory, intellectual, psychological and social functional levels. Rehabilitation provides disabled people with the tools they need to attain independence and self-determination.

A serious disruption of the functioning of a community or a society causing widespread human, material, economic or environmental losses which exceed the ability of the affected community or society to cope using its own resources.

Drowning is the process of experiencing respiratory impairment from submersion/immersion in liquid, which can result in death, morbidity or no morbidity. Major risk factors for drowning include age, sex, access to water, lack of effective supervision of children and the frequency of natural and water transport related disasters. In 2015, more than 78 000 people drowned in the Western Pacific Region, accounting for 22% of the global burden of drowning. It kills more children under than the age of 15 in the Western Pacific Region than tuberculosis, HIV/AIDS, malnutrition, measles, meningitis, dengue and malaria combined. In addition to the significant number of deaths, non-fatal drowning (where individuals are rescued and/or resuscitated) results in a substantial number of hospitalizations and impact on the health system. Despite the magnitude and preventability of drowning, priority for action is limited in many low- and middle-income countries.

The Western Pacific Region is vulnerable to health security and emergency risks brought about by disease outbreaks, emergencies and disasters. We work closely with Member States, experts and key partners. Through building core capacities, we make optimal use of available resources. Making our risk management approach focuses on the core capacities needed to address a wide range of hazards.

Essential medicines are those that satisfy the priority health care needs of the population. They are selected with due regard to public health relevance, evidence on efficacy and safety, and comparative cost-effectiveness. Essential medicines are intended to be available within the context of functioning health systems at all times in adequate amounts, in the appropriate dosage forms, with assured quality and adequate information, and at a price the individual and the community can afford.

Family planning allows individuals and couples to anticipate and attain their desired number of children and the spacing and timing of their births. It is achieved through use of contraceptive methods and the treatment of involuntary infertility. A woman’s ability to space and limit her pregnancies has a direct impact on her health and well-being as well as on the outcome of each pregnancy.

Foodborne diseases take a major toll on health. Millions of people fall ill and many die as a result of eating unsafe food. Deeply concerned by this, WHO Member States adopted a resolution in 2000 to recognize food safety as an essential public health function. Food safety encompasses actions aimed at ensuring that all food is as safe as possible. Food safety policies and actions need to cover the entire food chain, from production to consumption.

Gender refers to the socially constructed characteristics of women and men – such as the norms, roles and relationships that exist between them. Gender expectations vary between cultures and can change over time. It is also important to recognize identities that do not fit into the binary male or female sex categories. Gender norms, relations and roles also impact the health outcomes of people with transgender or intersex identities. http://www.who.int/mediacentre/factsheets/fs403/en/

Hand hygiene as part of an infection prevention and control programme in all settings that support surgery, prevents patient infection and reduces an avoidable burden on health systems.

Environmental health addresses all the physical, chemical, and biological factors external to a person, and all the related factors impacting behaviours. It encompasses the assessment and control of those environmental factors that can potentially affect health. It is targeted towards preventing disease and creating health-supportive environments. This definition excludes behaviour not related to environment, as well as behaviour related to the social and cultural environment, and genetics.

Statistics refers to both quantitative data, and the classification of such data in accordance with probability theory and the application to them of methods such as hypothesis testing. Health statistics include both empirical data and estimates related to health, such as mortality, morbidity, risk factors, health service coverage, and health systems. The production and dissemination of health statistics is a core WHO activity mandated to WHO by its Member States in its Constitution. WHO programmes compile and disseminate a broad range of statistics that play a key role in advocacy for health issues, monitoring and evaluation of health programmes and provision of technical assistance to countries.

Equity is the absence of avoidable or remediable differences among groups of people, whether those groups are defined socially, economically, demographically or geographically. Health inequities involve more than inequality with respect to health determinants, access to the resources needed to be healthy or health outcomes. They also entail a failure to avoid or overcome inequalities that infringe on fairness. Reducing health inequities is important because health is a fundamental human right. However, evidence suggests that the impressive health gains achieved over recent decades are unequally distributed and have largely failed to reach the poor and other marginalized or socially excluded groups. Persistent and growing inequalities in health are increasingly evident, both between and within countries.

Health financing is concerned with how financial resources are generated, allocated and used in health systems. Health financing policy focuses on how to move closer to universal coverage with issues related to: (i) how and from where to raise sufficient funds for health; (ii) how to overcome financial barriers that exclude many poor from accessing health services; or (iii) how to provide an equitable and efficient mix of health services

In line with the Region’s For the Future vision, WHO advocates a broader role for governments in health innovation in order to regain momentum towards WHO’s global goals and the Sustainable Development Goals health targets.

Health promotion helps reduce excess mortality, address the leading risk factors and underlying determinants of health, helps strengthen sustainable health systems, and places health at the centre of the broad development agenda.

WHO's Global School Health Initiative, launched in 1995, seeks to mobilize and strengthen health promotion and education activities at the local, national, regional and global levels. The Initiative is designed to improve the health of students, school personnel, families and other members of the community through schools.

Since 2005, Member States, WHO and partners have worked together to strengthen health security through updates of the Asia Pacific Strategy for Emerging Diseases and Public Health Emergencies. Developed with the WHO South-East Asia Region, the Strategy has supported countries in the Western Pacific to strengthen core public health capacities and systems that enabled effective responses to the COVID-19 pandemic.

Laboratory networks are essential to support disease surveillance and outbreak investigation. Formalized networks facilitate the exchange of knowledge and expertise, thus facilitating timely and appropriate support to surveillance and epidemiology. Laboratory biosafety procedures and practices describe ways to appropriately handle and work with pathogens, minimizing the risk of exposure and infection.

Health workers are "all people engaged in actions whose primary intent is to enhance health" (World Health Report 2006). Workers in health systems around the world are experiencing increasing stress and insecurity as they react to a complex array of forces. Ageing population, new diseases as well as increasing burden of current diseases, escalating conflicts and violence, are all challenges to which the workforce must be prepared to respond. The unmistakable imperative is to strengthen the workforce so that health systems can tackle crippling diseases and achieve national and global health goals. A strong human infrastructure is fundamental to closing today’s gap between health promise and health reality, and anticipating the health challenges of the 21st century.

Hepatitis is an inflammation of the liver, most commonly caused by a viral infection. There are five main hepatitis viruses, referred to as types A, B, C, D and E. These five types are of greatest concern because of the burden of illness and death they cause and the potential for outbreaks and epidemic spread. In particular, types B and C lead to chronic disease in hundreds of millions of people and, together, are the most common cause of liver cirrhosis and cancer. Hepatitis A and E are typically caused by ingestion of contaminated food or water. Hepatitis B, C and D usually occur as a result of parenteral contact with infected body fluids. Common modes of transmission for these viruses include receipt of contaminated blood or blood products, invasive medical procedures using contaminated equipment and for hepatitis B transmission from mother to baby at birth, from family member to child, and also by sexual contact. Acute infection may occur with limited or no symptoms, or may include symptoms such as jaundice (yellowing of the skin and eyes), dark urine, extreme fatigue, nausea, vomiting and abdominal pain.

The human immunodeficiency virus (HIV) is a retrovirus that infects cells of the immune system, destroying or impairing their function. As the infection progresses, the immune system becomes weaker, and the person becomes more susceptible to infections. The most advanced stage of HIV infection is acquired immunodeficiency syndrome (AIDS). It can take 10-15 years for an HIV-infected person to develop AIDS; antiretroviral drugs can slow down the process even further. HIV is transmitted through unprotected sexual intercourse (anal or vaginal), transfusion of contaminated blood, sharing of contaminated needles, and between a mother and her infant during pregnancy, childbirth and breastfeeding.

Hospitals play an important role in the health care system. They are health care institutions that have an organized medical and other professional staff, and inpatient facilities, and deliver medical, nursing and related services 24 hours per day, 7 days per week. Hospitals offer a varying range of acute, convalescent and terminal care using diagnostic and curative services in response to acute and chronic conditions arising from diseases as well as injuries and genetic anomalies. In doing so they generate essential information for research, education and management. Traditionally oriented on individual care, hospitals are increasingly forging closer links with other parts of the health sector and communities in an effort to optimize the use of resources for the promotion and protection of individual and collective health status.

Immunization is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine. Vaccines stimulate the body’s own immune system to protect the person against subsequent infection or disease.

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, an acid-fast, rod-shaped bacillus. The disease mainly affects the skin, the peripheral nerves, mucosa of the upper respiratory tract and also the eyes, apart from some other structures. Leprosy has afflicted humanity since time immemorial. It once affected every continent and it has left behind a terrifying image in history and human memory - of mutilation, rejection and exclusion from society.

Malaria is caused by parasites that are transmitted to people through the bites of infected female mosquitoes. P. falciparum is the most deadly malaria parasite and the most prevalent in Africa, where malaria cases and deaths are heavily concentrated. The first symptoms of malaria – fever, headache, chills and vomiting – usually appear between 10 and 15 days after the mosquito bite. Without prompt treatment, P. falciparum malaria can progress to severe illness and death. WHO recommends a multi-pronged strategy to prevent, control and eliminate malaria. Key interventions include: the use of insecticide-treated mosquito nets and indoor residual spraying, diagnostic testing, and treatment of confirmed cases with effective anti-malarial medicines. In recent years, these measures have dramatically lowered the malaria burden in many settings. Malaria transmission continues in many countries around the world however, and causes hundreds of thousands of deaths each year.

Maternal health refers to the health of women during pregnancy, childbirth and the postpartum period. While motherhood is often a positive and fulfilling experience, for too many women it is associated with suffering, ill-health and even death. The major direct causes of maternal morbidity and mortality include haemorrhage, infection, high blood pressure, unsafe abortion, and obstructed labour.

Measles is a highly contagious viral disease whose common complications include pneumonia and diarrhoea. Death may occur in up to 5-10% of infected young children in developing countries. Rubella is also a contagious viral disease, but milder than measles. However, when rubella infects a pregnant woman during the first half of her pregnancy, there is danger of fetal death or birth defects affecting primarily the eyes, ears, heart, and brain.

Course of study required to educate a legally qualified and licensed practitioner of medicine, concerned with maintaining or restoring human health through the study, diagnosis and treatment of disease and injury, through the science of medicine and the applied practice of that science. Gaining a basic medical degree may take from five to eight or even nine years, depending on jurisdiction and university. Medical doctors include generalists and specialists. Medical training completed by internship qualifies a medical doctor to become a physician or a surgeon.

Mental health refers to a broad array of activities directly or indirectly related to the mental well-being component included in the WHO's definition of health: "A state of complete physical, mental and social well-being, and not merely the absence of disease". It is related to the promotion of well-being, the prevention of mental disorders, and the treatment and rehabilitation of people affected by mental disorders. The harmful use of alcohol is a global problem which compromises both individual and social development. It results in 3.3 million deaths each year. Alcohol is the world's third largest risk factor for premature mortality, disability and loss of health; it is the leading risk factor in the Western Pacific and the Americas and the second largest in Europe. Alcohol is associated with many serious social and developmental issues, including violence, child neglect and abuse, and absenteeism in the workplace. It also causes harm far beyond the physical and psychological health of the drinker. It harms the well-being and health of people around the drinker. An intoxicated person can harm others or put them at risk of traffic accidents or violent behaviour, or negatively affect co-workers, relatives, friends or strangers. Thus, the impact of the harmful use of alcohol reaches deep into society.

Mobile clinics and medical teams reach people cut off from access to health services. For many people, these mobile clinics and teams may be their only source of health care. It offers flexible and viable options for treating isolated and vulnerable groups as well as to newly displaced populations.

Tropical diseases encompass all diseases that occur solely, or principally, in the tropics. In practice, the term is often taken to refer to infectious diseases that thrive in hot, humid conditions, such as malaria, leishmaniasis, schistosomiasis, onchocerciasis, lymphatic filariasis, Chagas disease, African trypanosomiasis, and dengue.

Noncommunicable diseases (NCDs), including heart disease, stroke, cancer, diabetes and chronic lung disease, are collectively responsible for almost 70% of all deaths worldwide. Almost three quarters of all NCD deaths, and 82% of the 16 million people who died prematurely, or before reaching 70 years of age, occur in low- and middle-income countries. The rise of NCDs has been driven by primarily four major risk factors: tobacco use, physical inactivity, the harmful use of alcohol and unhealthy diets.

WHO recognizes the vital role of nurses and midwives in keeping the world healthy. Comprising more than two-thirds of the health workforce in the Western Pacific Region, nurses are critical in responding to health needs in all settings and across the lifespan. In the 2020 International Year of the Nurse and the Midwife, the celebration of the World Health Day is an opportunity to highlight the work of nursing and midwifery around the world while celebrating this workforce as one of the most valuable resources of every country.

Nutrition is the intake of food, considered in relation to the body’s dietary needs. Good nutrition – an adequate, well balanced diet combined with regular physical activity – is a cornerstone of good health. Poor nutrition can lead to reduced immunity, increased susceptibility to disease, impaired physical and mental development, and reduced productivity.