Research Roundup: Identifying people at-risk for TB, a device to aid IUD insertion, and vaccines against cancer
One-third of the world’s population—more than 2 billion people—has latent tuberculosis (TB) and each year, 9.6 million people develop active TB. However, a team of scientists have identified 16 genes, referred to as a “risk signature,” that can predict which cases are most likely to progress to active TB. In two studies enrolling more than 10,000 participants across South Africa and Gambia, researchers collected and analyzed blood samples to detect the presence of the risk signature. The genes predicted cases of active TB with sensitive and specificity rates of 66.1 percent and 80.6 percent: in other words, two-thirds of the patients with the genetic risk signature developed active TB during the study, compared to only one-fifth of those without the risk signature. TB is the world’s leading infectious disease killer, resulting in 1.5 million deaths in 2014. However, the study suggests that this risk signature could be used to predict cases of active TB up to 18 months in advance, and treating latent TB can reduce the risk of developing the disease by 90 percent.
A new tool to easily insert intrauterine devices (IUDs)—long-acting contraceptive devices that can remain in the uterus for up to twelve years—could make the devices more accessible in low-resource settings. IUDs contain either copper, which is toxic to sperm, or hormones that preclude the release of eggs from the ovaries. The devices are safe and more than 99 percent effective, however, they can be difficult to insert. However, a new IUD inserter could make the contraceptive devices much more accessible, particularly for postpartum woman. The inserter was developed by Population Services International, in partnership with Stanford Program for International Reproductive Education and Services and Pregna International Ltd., costs just US$1, and is longer and sturdier than existing tools. In a trial enrolling 80 women in India each of whom had given birth just hours before, 90 percent of health workers reported that the IUD was easy to place with the new inserter and more than 90 percent of women felt no increase in pain during the procedure. Improved inserters could have a significant impact in settings without ultrasound technology—used to confirm the placement of the IUD—or with limited ability to sterilize equipment.
Next Billion took an in-depth look at existing vaccines to prevent and treat cancer, emphasizing their need in low-resource settings, where cancer testing and treatment are often inaccessible and prohibitively expensive. Rather than targeting pathogens, these vaccines train the immune system to attack cancerous cells. There are currently preventative vaccines available against strains of human papillomavirus (HPV) and hepatitis B virus that cause cervical and liver cancer, respectively, and other vaccines available and under development can prevent the spread or relapse of bladder, prostrate, and lung cancer.
Cervical cancer results in more deaths among women in low- and middle-income countries than any other type of cancer. Fortunately, HPV vaccines prevent against several strains of the virus, including the two responsible for 70 percent of cases. Liver cancer ranks second in cancer mortality worldwide, however, many cases could be averted with increased access to hepatitis B vaccines. Individuals infected with hepatitis B are 100 times more likely to develop liver cancer.
Lung cancer is the leading cause of death from cancer worldwide, and non-small cell lung cancer (NSCLC) accounts for 85 percent of cases. However, researchers in Cuba are developing a therapeutic vaccine against NSCLC, which has extended survival rates for patients by 68 percent in phase 3 trials. Additionally, the TB vaccine is used to fight bladder cancer and the vaccine Sipuleucel-T is used against advanced prostate cancer.