On March 11, 2020, the WHO declared the COVID-19 outbreak a pandemic, recognizing the global spread and severity of the disease caused by the novel coronavirus SARS-CoV-2. This declaration marked a significant escalation in the global response to the outbreak, prompting countries worldwide to implement measures to contain the virus and mitigate its impact on public health and economies.

On August 8, 2014, the WHO declared the Ebola outbreak in West Africa a Public Health Emergency of International Concern (PHEIC). This declaration was made to coordinate international response efforts and mobilize resources to combat the outbreak, which primarily affected Guinea, Liberia, and Sierra Leone. The WHO played a critical role in managing the crisis and supporting affected countries.

The International Health Regulations (IHR) of 2005 were adopted by the World Health Assembly to provide a legal framework for the international community to prevent and respond to acute public health risks. The IHR (2005) aim to enhance national, regional, and global public health security and improve the capacity of all countries to detect, assess, report, and respond to public health threats.

On March 12, 2003, the WHO issued a global alert about Severe Acute Respiratory Syndrome (SARS), a new infectious disease that had emerged in Asia. The alert was part of the WHO's efforts to contain the outbreak, which eventually spread to over two dozen countries. The WHO's response included coordinating international efforts to identify the virus and implement public health measures.

In 1988, the WHO, along with Rotary International, UNICEF, and the U.S. Centers for Disease Control and Prevention, launched the Global Polio Eradication Initiative (GPEI). The initiative aimed to eradicate polio worldwide through widespread immunization campaigns. Since its inception, GPEI has significantly reduced polio cases globally and continues to work towards complete eradication.

The Alma-Ata Declaration was adopted at the International Conference on Primary Health Care in 1978, co-sponsored by the WHO and UNICEF. Held in Alma-Ata, USSR (now Almaty, Kazakhstan), the declaration emphasized the importance of primary health care and set the goal of achieving 'Health for All' by the year 2000. It remains a foundational document in global health policy.

The WHO launched the Expanded Programme on Immunization (EPI) in 1974 to ensure that all children have access to vaccines for preventable diseases. The program initially focused on six diseases: tuberculosis, poliomyelitis, diphtheria, tetanus, pertussis, and measles. EPI has significantly increased global vaccination coverage and reduced child mortality rates.

The WHO established the International Agency for Research on Cancer (IARC) in 1965 to promote international collaboration in cancer research. Based in Lyon, France, IARC conducts and coordinates research on the causes of cancer, mechanisms of carcinogenesis, and develops scientific strategies for cancer control. It plays a crucial role in global cancer research and prevention.

In 1955, the WHO launched the Global Malaria Eradication Programme, aiming to eliminate malaria worldwide through the use of insecticides and antimalarial drugs. Although the program achieved significant reductions in malaria cases in some regions, it faced challenges in others, leading to its eventual discontinuation in 1969. The program's legacy influenced future malaria control efforts.

The World Health Organization (WHO) was established on April 7, 1948, as a specialized agency of the United Nations responsible for international public health. Its founding marked a significant step in global health governance, aiming to address health issues on a worldwide scale. The WHO's constitution was signed by 61 countries in New York City, and it began operations on this date.