Arthropod vectors, including insects and ticks, can transmit infectious disease pathogens among humans or between animals and humans. Arthropod vectors are responsible for the spread and transmission of malaria, dengue fever, chikungunya, yellow fever, Zika, leishmaniasis, Chagas disease, and Lyme disease. According to the World Health Organization, malaria, which is transmitted by mosquitoes, caused an estimated 627,000 deaths in 2020, most of them children under 5 years of age. Other vector-borne diseases such as Chagas disease, leishmaniasis, and schistosomiasis affect hundreds of millions of people worldwide. The burden of these diseases is highest in tropical and subtropical areas, and they disproportionately affect the poorest populations.

NIAID conducts and supports a comprehensive vector biology research program to advance science and identify approaches that will help control or prevent the transmission of vector-borne pathogens to humans. This includes basic research to better understand the biology of arthropod vectors, how they transmit diseases, and how they find and interact with human hosts. The program also supports translational and clinical research to identify and evaluate products and approaches designed to affect vector populations and/or prevent the transmission of pathogens. This includes the development of traps and repellents, the use of biologicals such as Wolbachia bacteria, and the evaluation of novel candidate vaccines based on mosquito saliva.

In 2024, the U.S. Department of Health and Human Services released the National Public Health Strategy to Prevent and Control Vector-Borne Diseases in People (VBD National Strategy). The strategy identifies and describes federal priorities to detect, prevent, respond to, and control diseases and conditions caused by vectors in the United States. It represents the largest formal federal coordination effort focused on vector-borne disease prevention and control with contributions across 17 federal agencies.

Vaccines stimulate the immune system to produce immune responses that protect against infection. Vaccines provide a safe, cost-effective and efficient means of preventing illness, disability and death from infectious diseases.

Vaccines have saved millions of lives worldwide and dramatically reduced the prevalence of many life-threatening infectious diseases. Yet there remains a need for new and improved vaccines against existing infectious diseases, as well as a need for rapid development of experimental vaccines to address emerging infectious diseases. NIAID supports and conducts research to identify new vaccine candidates to prevent a variety of infectious diseases, including those for which no vaccines currently exist. NIAID-supported research also aims to improve the safety and efficacy of existing vaccines.

Vaccine Research at NIAID

NIAID conducts and supports numerous stages of the vaccine development process, ranging from basic immunology research to clinical testing of candidate vaccines. Basic research aims to understand the complex interactions between pathogens and their human hosts and generate the knowledge essential for developing safe and effective vaccines. Preclinical research helps advance promising vaccine candidates into human testing. Clinical trials evaluate the safety, tolerability and efficacy of investigational vaccines in people.

The emergence and re-emergence of infectious diseases continues to threaten the health of Americans and people worldwide. In the past two decades NIAID has mounted major research responses and developed effective countermeasures to emerging infectious diseases including those caused by SARS-CoV-1, the 2009 H1N1 influenza virus, Middle East Respiratory Syndrome coronavirus (MERS-CoV), Ebola virus, Zika virus, and most recently SARS-CoV-2. The ongoing 2020 global pandemic caused by SARS-CoV-2 further has underscored the continual threat of newly emerging and re-emerging pathogens and the critical value of research in pandemic preparedness efforts.

To prepare for future public health emergencies caused by infectious diseases, NIAID has developed a Pandemic Preparedness Plan that leverages its broad research portfolio, long-standing expertise in product development, capacity to engage both domestic and international partners, and flexible infrastructure. While it is recognized that pathogens other than viruses could lead to public health emergencies, the NIAID Pandemic Preparedness Plan focuses on viruses that could cause epidemics or pandemics.

Goals for the NIAID Pandemic Preparedness Plan

• Systematically characterize pathogens of concern and increase research and surveillance to identify threats before they emerge
• Shorten timelines between pathogen emergence or outbreak onset and authorization/approval of candidate diagnostics and medical countermeasures, such as therapeutics and vaccines
• Bridge or eliminate existing gaps in research, infrastructure, and technology and expand pre-clinical and clinical testing capacity

Neglected tropical diseases (NTDs), such as dengue, lymphatic filariasis, trachoma, and leishmaniasis, are called "neglected," because they generally afflict the world's poor and historically have not received as much attention as other diseases. NTDs tend to thrive in developing regions of the world, where water quality, sanitation, and access to health care are substandard. However, some of these diseases also are found in areas of the United States with high rates of poverty.

Why Is the Study of Neglected Tropical Diseases a Priority for NIAID?

Neglected tropical diseases, take a tremendous toll on global health. The World Health Organization estimates that more than one billion people — approximately one-sixth of the world's population — suffer from at least one NTD. While NTDs rarely lead to death, they can cause significant disability that persists for a lifetime, including fatigue, blindness, and disfigurement. Sufferers miss school, are unable to work, or are too embarrassed to seek medical care. By diminishing quality of life and opportunities to succeed, NTDs can reinforce the cycle of poverty among the world's disadvantaged populations.

How Is NIAID Addressing This Critical Topic?

NIAID has a robust program of research devoted to better understanding, preventing, and treating NTDs. Studies conducted and supported by NIAID have led to important new discoveries about the microbes that cause NTDs, the identification of targets for potential new drugs and vaccines, and the development of strategies for controlling the organisms that transmit NTD-causing agents to humans. Learn more about the NIAID role in neglected tropical disease research.

The immune system is a network of cells, tissues, and organs that work together to protect the body from infection.

Although scientists have learned much about the immune system, they continue to study how the body targets invading microbes, infected cells, and tumors while ignoring healthy tissues.

The combination of new technology and expanded genetic information promises to reveal more about how the body protects itself from disease. In turn, scientists can use this information to develop new strategies for the prevention and treatment of infectious and immune-mediated diseases.

Global research is an integral part of many research projects, programs, initiatives, and other activities implemented by the NIAID extramural and intramural divisions. Conducting research in international settings allows NIAID-supported scientists to study infectious diseases and immunology under a variety of environmental and social conditions. It also provides opportunities to study the effectiveness of investigational drugs and vaccines in populations that vary genetically and immunologically, in the hope of finding treatments and preventions for wide ranges of disease strains and mutations. By working with partners in academia, private industry, philanthropic foundations, and other research-supporting agencies, NIAID enhances research that improves the quality of human life both in the United States and around the world.

The discoveries made help improve the health of millions of individuals, advance public health policy and clinical practice, protect the United States against infectious disease threats, and promote international wellbeing. In executing its mandate, NIAID helps lead global health research, health diplomacy, and the global effort to defeat infectious, immunologic, and allergic diseases.

Learn more about NIAID's Role in Global Research.

Research fields, such as genomics, proteomics, and systems biology, are creating a wealth of information about infectious and immune-mediated diseases. Through the use of advanced technologies, researchers are developing a clearer understanding of pathogens, disease, and host immunity.

Advanced technologies research fields, such as genomics, proteomics, and bioinformatics, hold great promise for developing new diagnostics, therapeutics, and vaccines to treat and prevent infectious and immune-mediated diseases.

NIAID has made a significant commitment to support and encourage advanced technologies research in Institute labs and in the scientific community. Sophisticated tools are being used to determine the genetic make-up of disease-causing pathogens, to analyze discrepancies among pathogen strains, and to evaluate how immune system responses differ.

NIAID supports research and early development of medical countermeasures against terrorist threats from infectious diseases, radiation exposure and chemical threats to the civilian population.

Why Are Biodefense And Related Programs a Priority for NIAID?

After the events of September 11, 2001, and the subsequent anthrax mailings, biodefense became an important element of the NIAID mission. In 2003, NIAID was assigned lead responsibility within the U.S. Department of Health and Human Services (HHS) and the National Institutes of Health (NIH) for civilian biodefense research with a focus on research and early development of medical countermeasures against terrorist threats from infectious diseases and radiation exposure. NIAID later assumed responsibility for coordinating the NIH‐wide effort to develop medical countermeasures against chemical threats to the civilian population.

How Is NIAID Addressing This Critical Topic?

NIAID supports research and early development of medical countermeasures against terrorist threats from infectious diseases, radiation exposure and chemical threats to the civilian population. Because new potentially deadly pathogens, such as avian influenza, may be naturally occurring as well as deliberately introduced by terrorists, NIAID’s biodefense research is integrated into its larger emerging and re‐emerging infectious diseases portfolio. While NIAID continues to focus on developing drugs, vaccines, and diagnostics for these disease agents, the research focus has evolved from the traditional “one bug–one drug” approach to a more flexible strategy using sophisticated genomic and proteomic platforms focused on developing broad‐spectrum therapies effective against entire classes of pathogens.

Bacteria, fungi, and other microbes evolve over time and can develop resistance to antimicrobial drugs. Microbes naturally develop resistance; however, using antibiotics too often in humans and animals and in cases where antibiotics are not an appropriate treatment can make resistance develop more quickly.

Antimicrobial resistance is a significant public health problem in the U.S. and around the world as infections are becoming increasingly difficult to treat, especially in healthcare facilities and in people with weakened immune systems.

To address this growing problem, NIAID is funding and conducting research to better understand how microbes develop and pass on resistance genes. NIAID is also supporting the development of new and faster diagnostic tests to make it easier for doctors to prescribe the most effective drug. NIAID’s research program also focuses on ways to prevent infections, including vaccines, and developing new antibiotics and novel treatments effective against drug-resistant microbes.