- First World War
- The ABO blood group system was discovered in 1901, and the Rhesus group in 1937, facilitating blood transfusion.
- During the 20th century, large-scale wars were attended with medics and mobile hospital units which developed advanced techniques for healing massive injuries and controlling infections rampant in battlefield conditions. Thousands of scarred troops provided the need for improved prosthetic limbs and expanded techniques in plastic surgery or reconstructive surgery. Those practices were combined to broaden cosmetic surgery and other forms of elective surgery.
- During the First World War, Alexis Carrel and Henry Dakin developed the Carrel-Dakin method of treating wounds with an irrigation, Dakin's solution, a germicide which helped prevent gangrene.
- The Great War spurred the usage of Roentgen's X-ray, and the electrocardiograph, for the monitoring of internal bodily functions. This was followed in the inter-war period by the development of the first anti-bacterial agents such as the sulpha antibiotics.
The 1918 flu pandemic killed at least 50 million people around the world. It became an important case study in epidemiology. Bristow shows there was a gendered response of health caregivers to the pandemic in the United States. Male doctors were unable to cure the patients, and they felt like failures. Women nurses also saw their patients die, but they took pride in their success in fulfilling their professional role of caring for, ministering, comforting, and easing the last hours of their patients, and helping the families of the patients cope as well.
From 1917 to 1923, the American Red Cross moved into Europe with a battery of long-term child health projects. It built and operated hospitals and clinics, and organized antituberculosis and antityphus campaigns. A high priority involved child health programs such as clinics, better baby shows, playgrounds, fresh air camps, and courses for women on infant hygiene. Hundreds of U.S. doctors, nurses, and welfare professionals administered these programs, which aimed to reform the health of European youth and to reshape European public health and welfare along American lines.
- Second World War:
American combat surgery during the Pacific War, 1943. Major wars have stressed the need for qualified medicaltreatment and hygiene
The advances in medicine made a dramatic difference for Allied troops, while the Germans and especially the Japanese and Chinese suffered from a severe lack of newer medicines, techniques and facilities. Harrison finds that the chances of recovery for a badly wounded British infantryman were as much as 25 times better than in the First World War. The reason was that:
"By 1944 most casualties were receiving treatment within hours of wounding, due to the increased mobility of field hospitals and the extensive use of aeroplanes as ambulances. The care of the sick and wounded had also been revolutionized by new medical technologies, such as active immunization against tetanus, sulphonamide drugs, and penicillin."
Nazi and Japanese medicine:
Human subject research, and killing of patients with disabilities, were at the nadir during the Nazi era, with Nazi human experimentation and Aktion T4 during the Holocaust as the most significant example, followed up by the Doctors' Trial. Principles of medical ethics, such as the Nuremberg Code, have been introduced to prevent such atrocities. After 1937, the Japanese Army established programs of biological warfare in China. In Unit 731, Japanese doctors and research scientists conducted large numbers of vivisections and experiments on human beings, mostly Chinese victims.
Starting in World War II, DDT was used as insecticide to combat insect vectors carrying malaria, which was endemic in most tropical regions of the world. The first goal was to protect soldiers, but it was widely adopted as a public health device. In Liberia, for example, the United States had large military operations during the war and the U.S. Public Health Service began the use of DDT for indoor residual spraying (IRS) and as a larvicide, with the goal of controlling malaria in Monrovia, the Liberian capital. In the early 1950s, the project was expanded to nearby villages. In 1953, the World Health Organization (WHO) launched an antimalaria program in parts of Liberia as a pilot project to determine the feasibility of malaria eradication in tropical Africa. However these projects encountered a spate of difficulties that foreshadowed the general retreat from malaria eradication efforts across tropical Africa by the mid-1960s.
Post-World War II:
Smallpox vaccination in Niger, 1969. A decade later, this was the first infectious disease to be eradicated
Most countries have seen a tremendous increase in life expectancy since 1945. However, in southern Africa, theHIV epidemic beginning around 1990 has eroded national health
A cochlear implant is a common kind of neural prosthesis, a device replacing part of the human nervous system
The World Health Organization was founded in 1948 as a United Nations agency to improve global health. In most of the world, life expectancy has improved since then, and was about 67 years as of 2010, and well above 80 years in some countries. Eradication of infectious diseases is an international effort, and several new vaccines have been developed during the post-war years, against infections such as measles, mumps, several strains of influenza and human papilloma virus. The long-known vaccine against Smallpox finally eradicated the disease in the 1970s, and Rinderpest was wiped out in 2011. Eradication of polio is underway. Tissue culture is important for development of vaccines. Though the early success of antiviral vaccines and antibacterial drugs, antiviral drugs were not introduced until the 1970s. Through the WHO, the international community has developed a response protocol against epidemics, displayed during the SARS epidemic in 2003, and the Influenza A virus subtype H5N1 from 2004 and onwards.
As infectious diseases have become less lethal, and the most common causes of death in developed countries are now tumors and cardiovascular diseases, these conditions have received increased attention in medical research. Tobacco smoking as a cause of lung cancer was first researched in the 1920s, but was not widely supported by publications until the 1950s. Cancer treatment has been developed with radiotherapy, chemotherapy and surgical oncology.
Oral rehydration therapy has been extensively used since the 1970s to treat cholera and other diarrhea-inducing infections.
Hormonal contraception was introduced in the 1950s, and was associated with the sexual revolution, with normalization of abortion and homosexuality in many countries. Family planning has promoted a demographic transition in most of the world. With threatening sexually transmitted infections, not least HIV, use of barrier contraception has become imperative. The struggle against HIV has improved antiretroviral treatments, and in the late 2000s (decade), male circumcision was cited to diminish infection risk. In 2013, the first patient was cured from HIV.
X-ray imaging was the first kind of medical imaging, and later ultrasonic imaging, CT scanning, MR scanning and other imaging methods became available.
Genetics have advanced with the discovery of the DNA molecule, genetic mapping and gene therapy. Stem cell research took off in the 2000s (decade), with stem cell therapy as a promising method.
Evidence-based medicine is a modern concept, not introduced to literature until the 1990s.
Prosthetics have improved. In 1958, Arne Larsson in Sweden became the first patient to depend on an artificial cardiac pacemaker. He died in 2001 at age 86, having outlived its inventor, the surgeon, and 26 pacemakers. Lightweight materials as well as neural prosthetics emerged in the end of the 20th century.
Cardiac surgery was revolutionized in the late 1940s, as open-heart surgery was introduced.
In 1954 Joseph Murray, J. Hartwell Harrison and others accomplished the first kidney transplantation. Transplantations of other organs, such as heart, liver and pancreas, were also introduced during the latter 20th century. The first partial face transplant was performed in 2005, and the first full one in 2010. By the end of the 20th century, microtechnology had been used to create tiny robotic devices to assist microsurgery using micro-video and fiber-optic cameras to view internal tissues during surgery with minimally invasive practices.
Laparoscopic surgery was broadly introduced in the 1990s. Natural orifice surgery has followed. Remote surgery is another recent development, with the Lindbergh operation in 2001 as a groundbreaking example.