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Infectious Disease

Global Health, Infectious Disease, Public Health, Research, Stanford News

Using video surveillance to gain insights into hand washing behavior

Using video surveillance to gain insights into hand washing behavior

13715-handwashing_newsSimply washing your hands can reduce the reduce respiratory illnesses, such as colds, in the general public by 21 percent, cut the number of people who get sick with diarrhea by 31 percent and lower diarrheal illness in people with weakened immune systems by 58 percent, according to data from the Centers for Disease Control and Prevention.

Despite these compelling facts, and many years of global awareness campaigns, hand-cleaning rates remain far below full compliance — particularly in low-income, developing world settings. But using video surveillance to observe hygiene practices can offers insights that may help improve design, monitoring and evaluation of hand-washing campaigns, according to a new Stanford study.

For the study, researchers installed video cameras at the washing stations outside latrines of four public schools in the Kibera slum of Nairobi, Kenya. Teachers were informed in advance and parents and administrators granted their permission for the experiment. Their findings were highlighted in a Stanford News article published yesterday:

  • Both video observation and in-person observation demonstrated longer hand cleaning times for hand washing with soap as compared to rubbing with sanitizer.
  • Students at schools equipped with soap and water, instead of sanitizer, were 1.3 times more likely to wash their hands during simultaneous video surveillance and in-person observation when compared with periods of in-person observation alone.
  • Overall, when students were alone at a hand-cleaning station, hand cleaning rates averaged 48 percent, compared to 71 percent when at least one other student was present.

Based on their findings, study authors recommended the following approaches for boosting hand washing:

  • Placement of hand cleaning materials in public locations
  • Scheduling specific times for bathroom breaks between classes
  • Designating specific students to be hand hygiene “champions”
  • Formation of student clubs to demonstrate and promote hand hygiene to classmates

Previously: Examining the effectiveness of hand sanitizers, Survey outlines barriers to handwashing in schools, Examining hand hygiene in the emergency department, Good advice from Washyourhandsington and Hey, health workers: Washing your hands is good for your patients
Photo by Amy Pickering

Global Health, Infectious Disease, Technology

Health workers use crowdsourced maps to respond to Ebola outbreak in Guinea

Médecins Sans Frontières and other international aid organizations are furiously working to contain an outbreak of Ebola in Guinea and nearby African countries. Latest reports estimate that the virus has infected 157 people and killed 101 in Guinea alone.

A New Scientist story published today explains how health workers from Médecins Sans Frontières were initially at a disadvantage when they arrived in Guinea to combat the deadly virus because they only had topographic charts to use in pinpointing the source of the disease. Desperately in need of maps that would be useful in understanding population distribution, the organization turned to Humanitarian OpenStreetMap Team, which coordinated a crowdsourcing effort to produce the first digital map of Guéckédou, a city of around 250,000 people in southern Guinea. Hal Hodson writes:

As of 31 March, online maps of Guéckédou were virtually non-existent, says Sylvie de Laborderie of cartONG, a mapping NGO that is working with MSF to coordinate the effort with HOT. “The map showed two roads maybe – nothing, nothing.”

Within 12 hours of contacting the online group, Guéckédou’s digital maps had exploded into life. Nearly 200 volunteers from around the world added 100,000 buildings based on satellite imagery of the area, including other nearby population centres. “It was amazing, incredible. I have no words to describe it. In less than 20 hours they mapped three cities,” says de Laborderie.

Mathieu Soupart, who leads technical support for MSF operations, says his organisation started using the maps right away to pinpoint where infected people were coming from and work out how the virus, which had killed 95 people in Guinea when New Scientist went to press, is spreading. “Having very detailed maps with most of the buildings is very important, especially when working door to door, house by house,” he says. The maps also let MSF chase down rumours of infection in surrounding hamlets, allowing them to find their way through unfamiliar terrain.

Previously: Using crowdsourcing to diagnose malaria and On crowdsourced relief efforts in Haiti

Global Health, Immunology, Infectious Disease, Microbiology, Research, Stanford News

Discovered: Why so many people with schistosomiasis (there’s a lot of them) are so vulnerable to bacterial co-infection

Discovered: Why so many people with schistosomiasis (there's a lot of them) are so vulnerable to bacterial co-infection

More than a billion people worldwide – almost all of them in developing countries – are infected by worm-like parasitic organisms called helminths. Organisms making up just a single genus of helminth, Schistosoma, account for one-quarter of those infections, which damage different body parts depending on what schistosomal species is doing the infecting. Some go for the lung. Others (card-carrying members of the species Schistosoma haematobium) head for the urinary tract, with one in ten infected patients suffering severe physical consequences.

People with schistosomiasis of the urinary tract are especially vulnerable to bacterial co-infections. Worse, these co-infections exacerbate an already heightened risk of bladder cancer in infected individuals, it’s believed. Unfortunately, considering the massive numbers of cases, surprisingly little is understood about the molecular aspects of the infection’s course.

A big reason for that relative ignorance has been the absence of an effective animal model enabling the detailed study of urinary-tract schistosomiasis. A couple of years ago, Stanford schistosomiasis expert Mike Hsieh, MD, PhD, developed the world’s first decent mouse model for the disease, allowing him to explore the molecular pathology that occurs early in the course of infection. Now, in a just-published study in Infection and Immunity, Hsieh has put that mouse model to work in coaxing out the cause of the curious collegiality of S. haematobium and co-infecting bacteria.

The secret, the scientists learned, is that S. haemotobium infection induces a spike in levels of a circulating immune-system signaling protein, or cytokine, called IL-4. That excess, in turn, results in a drop in the number and potency of a subset of immune cells that are important in fighting off bacterial infections. The discovery opens a pathway toward the development of new, non-antibiotic drug treatments for co-infected patients that won’t wreak havoc with their microbiomes, as antibiotics typically do.

Previously: Is the worm turning? Early stages of schistosomiasis bladder infection charted, Neglected story of schistosomiasis in Ghana, as told in a  sand animation and A good mouse model for a bad worm

Global Health, HIV/AIDS, Infectious Disease, Stanford News

Stanford study: South Africa could save millions of lives through HIV prevention

Stanford study: South Africa could save millions of lives through HIV prevention

South Africa could save the lives of some 4.5 million people over the next 20 years by using a double-barreled approach to HIV prevention.

That’s the result of a new study by Stanford researchers who looked at two methods for helping contain the epidemic in South Africa. According to the latest figures from the United Nations Joint Programme on HIV/AIDS, South Africa is the world’s hardest-hit country with 6.1 million people infected with HIV and most new infections happening via heterosexual transmission.

Effectively targeting people who don’t use condoms and have many sexual partners would prevent many infections and avert the costs of having to treat people down the road

One way to prevent sexual transmission of the disease is to give antiretroviral therapy to individuals as soon as they are found to be HIV-positive, said Sabina Alistar, PhD, first author of the new study. The World Health Organization now recommends that people go on ARV treatment when their CD4 counts – a measure of their immune system function – fall below 500. But a landmark study, published in 2011, showed that if infected individuals are effectively taking ARV treatment, the chance of their passing on the virus falls by a staggering 96 percent. So the greater the number of infected people on treatment, the less the virus will spread through the population.

“It’s much more cost-effective to put people in treatment as you find them, regardless of how far along they’ve progressed, rather than wait until they get really sick and put them on treatment,” said Alistar, who did the study while a PhD candidate in Management Science and Engineering at Stanford.

That idea isn’t new, but in this latest study from Stanford, the researchers examined the benefits of combining that universal approach to therapy with another tool, creating a powerful, cost-effective strategy for preventing millions of infections over time. The added tool, known as pre-exposure prophylaxis, or PrEP, involves daily use of a pill containing an antiretroviral drug. The pill is taken by people who may be at risk for HIV but are not infected. A landmark 2010 trial found that PrEP, if used faithfully, can reduce the risk of acquiring the virus by up to 73 percent.

“If you could focus on getting PrEP to people who engage in risky behaviors, then you could get quite significant results,” Alistar said. “Effectively targeting people who do not use condoms and have many sexual partners would prevent many infections and avert the costs of having to treat people down the road.”

She and her colleagues calculated that combining the two strategies – universal therapy for all those with HIV and targeted PrEP therapy for uninfected, high-risk individuals – would cost $150 per quality-adjusted life year gained (a QALY is measure of how much health benefit is gained for every dollar invested). That is a highly valuable bargain for South Africa, she said, which has significant resources to invest in the epidemic.

Eran Bendavid, MD, an assistant professor of medicine at Stanford and senior author of the paper, said scientists are now developing an approach to PrEP that only requires an injection every three or four months, rather than a daily pill.

When that therapy becomes available, “That has the potential to become a game-changer, since the Achilles heel of PrEP is low adherence,” Bendavid said.

The paper appears online today in the journal BMC Medicine.

Previously: U.S. AIDS Czar tells Stanford audience that witnessing death is a powerful motivatorTask force recommends HIV screening for all people aged 15 to 65International AIDS conference ends on an optimistic note and Using family planning counseling to reduce number of HIV-positive children in Africa

Clinical Trials, Global Health, Infectious Disease, Pediatrics, Stanford News

Life-saving dollar-a-dose rotavirus vaccine attains clinical success in advanced India trial

Life-saving dollar-a-dose rotavirus vaccine attains clinical success in advanced India trial

dollar bill 2Nearly every child in the world has been infected with rotavirus at least once by the age of five. But kids in poor countries get the worst of it. Rotavirus mortality is low in the developed world, but in low-income countries it’s a killer, accounting for 85 percent of the estimated 180,000 to 400,000 annual deaths caused by the pathogen.

The disparity exists for at least two reasons.

First, widespread malnutrition results in a different epidemiology. For example, 70 percent of rotavirus hospitalizations in India happen the first year of life, compared with 40 percent in high- and middle-income countries.

Second, price. Vaccination is second only to gaining access to potable water as a low-cost, high-payoff  strategy for ensuring children’s health. But many vaccines are far too pricey for families living on incomes in the neighborhood of $1,500 per year. As a result, most childhood deaths from vaccine-preventable diseases happen in low-income countries. India has the most rotavirus deaths in the world, estimated at about 75,000-122,000 per year (close to a quarter of the worldwide total.)

So it’s great news that a new rotavirus vaccine developed by Indians for Indians has leaped the safety and efficacy thresholds of a late-stage clinical trial, in which more than 6,500 Indian infants were inoculated, and will likely become available in that country for less than a dollar a dose. (The full immunization procedure requires three separate doses.)

The results appear in a study just published in The Lancet and co-authored by a team including veteran rotavirus-vaccine developer Harry Greenberg, MD. An accompanying perspective piece co-written by Greenberg, who also directs the Stanford Center for Clinical and Translational Research and Education, states:

[P]roof of the efficacy of the… vaccine against a disease that affects almost every child in India, leads to millions of clinic visits and hundreds of thousands of hospital admissions, and kills roughly one child in every 175-200 born in India before their fifth birthday is cause for celebration.

The new vaccine was the first to be fully tested for efficacy in a randomized, double-blind, placebo-controlled clinical trial in India. Interestingly, its development began with the discovery, by an Indian pediatrician, that newborns were getting rotavirus infections in the hospital but not getting sick. The strain they were infected with turned out to be an attenuated mutant virus that turns on the body’s immune response without causing symptoms: in short, the ideal vaccine candidate.

Ultimately spearheaded by a young Indian biotechnology company, Bharat Biotech, the effort to capitalize on this promising episode of serendipity drew financial support from the Bill & Melinda Gates Foundation and technical assistance from the Government of India’s Department of Biotechnology, the United States’ Centers for Disease Control and Prevention, and Stanford, among others.  This international team of collaborators then spent more than 15 years turning the promise into a reality.

Previously: Trials, and tribulations, of a rotavirus vaccine
Photo by David Guo

Infectious Disease, Public Health, Research

Could self-administered flu vaccine patches replace injections?

Could self-administered flu vaccine patches replace injections?

vaccine_patchLike many of us, I loathe getting shots. But after a serious case of the flu while on vacation led to an emergency room visit, I began to overlook my fear of needles and now get an annual flu shot. Still, I was interested to read about new research showing that self-administration of flu vaccines with microneedle patches, which can be painlessly pressed into outer layers of the skin, may one day be feasible.

In the study, researchers tested if individuals could successfully apply a prototype vaccine patch to themselves. Participants, none of whom had any previous experience with microneedle patches, were given instructions on how to apply them. Those involved in the study applied three patches to themselves and had a member of the research team apply a fourth. Individuals also received an injection of saline with a conventional hypodermic needle.

A release describes the study results and speculates on the significance of the findings for boosting vaccine rates:

The researchers evaluated how well the volunteers were able to self-administer the microneedle patches. After the subjects pressed the patches into their skin, the researchers applied a dye to highlight the tiny holes made by the microneedles. By photographing the administration sites and counting the number of holes, they were able to assess the accuracy of the application.

“We found that everyone was capable of administering a microneedle patch appropriately, though not everyone did on the first try,” [said Mark Prausnitz, PhD, a professor in the School of Chemical and Biomolecular Engineering at the Georgia Institute of Technology].

Some of the subjects used an applicator that made a clicking sound when sufficient force was applied to the patch. Use of that feedback device improved the ability of subjects to correctly apply patches and virtually eliminated administration mistakes.

During the study, the volunteers were asked if they planned to receive a flu vaccination in the next year and if their intent to be vaccinated would change if it could be done with the patch. The percentage saying they’d be vaccinated jumped from 46 to 65 percent when the patch was an option.

“If this holds for the population as a whole, that would have a tremendous impact on preventing disease and the cost associated with both influenza and the vaccination process,” said Paula Frew, an assistant professor in the Emory University School of Medicine and a co-author of the study.

Previously: Scientists develop technique to deliver dried vaccines to the skin without a needle, Laser-powered needle holds potential for delivering pain-free injections and Taking the sting out of injections
Photo by Gary Meek

Cancer, Infectious Disease, Pediatrics, Public Health, Research, Sexual Health

Girls don’t have riskier sex after the HPV vaccine

Girls don't have riskier sex after the HPV vaccine

HPV vaccineWhen the first vaccines were introduced against the human papillomavirus, some people worried that this anti-cancer vaccine would give young women the wrong idea. The vaccines, which protect against common cancer-causing strains of HPV, don’t guard against other sexually transmitted infections or unwanted pregnancies. But some parents and physicians thought that vaccine recipients might forgo condoms more often, have more sexual partners or otherwise engage in riskier sexual behaviors than women who were not vaccinated.

However, a study published today in Pediatrics says that’s not the case. According to the new research, young women don’t change their sexual behaviors after receiving the HPV vaccine. The researchers asked more than 300 girls and women, aged 13 to 21, about their risk perception and their sexual behaviors when they received their first dose of the HPV vaccine. They followed the group over time, repeating the questions 2 and 6 months later, when the vaccine’s booster shots were delivered.

“Most participants in this study did not perceive that they had a lower risk for STIs other than HPV, and most believed that safer sexual behaviors were still important,” the study’s authors wrote. Later, they add, “These findings contribute to the growing literature suggesting that HPV vaccination is unlikely to alter sexual risk behaviors in young women.”

I asked Stanford’s Sophia Yen, MD, for her take on the results. Yen provides HPV vaccinations in her role as an adolescent medicine specialist at the Teen and Young Adult Clinic at Lucile Packard Children’s Hospital Stanford. “The findings are not surprising and re-emphasize what other studies have shown,” she told me, adding that she hopes the study will be repeated in males, since boys have now begun receiving the HPV vaccine, too.

In the meantime, Yen plans to continue using this and other scientific evidence to reassure parents about the value of the vaccine. “I hope that the findings of this study and its many other predecessors will become widely known to parents and other non-adolescent medicine specialists who see adolescents, and to policymakers,” she said. “Let’s prevent STDs and cervical cancer together.”

Previously: Study shows racial disparities in HPV vaccination, Packard Children’s adolescent and young-adult specialist offers tips for college-bound students, HPV-associated cancers are rising, HPV vaccination rates still too low, new national report says and Only one-third of teenage girls get HPV vaccine to prevent cervical cancer
Photo by wintersoul1

In the News, Infectious Disease, Men's Health, Public Safety, Research, Stanford News

Exploring how gender affects the immune system

Exploring how gender affects the immune system

man_coldA piece published today on Slate examines how sex hormones, like estrogen and testosterone, may impact the strength of men and women’s immune systems. As noted in the article, recent research from Stanford immunologist Mark Davis, PhD, who directs Stanford’s Institute for Immunity, Transplantation and Infection, and his colleagues offers new insights on the issue:

… it’s been difficult to establish any direct link between levels of sex hormones circulating in the blood and the performance of men’s and women’s immune systems.

Recent research is now beginning to firmly establish that link. This month, a team of scientists at Stanford University has reported some of the best evidence yet that testosterone directly influences immune system function in men. The researchers took blood samples from male and female volunteers who were given a flu shot. Women had higher levels of immune system molecules circulating in their blood than men, and they produced more effective antibodies against the flu virus. And there were not only differences between men and women, but there were differences among men—the men with the weakest response to the flu shot had high levels of both testosterone and testosterone-induced enzymes, suggesting that high levels of testosterone can suppress immunity.

This finding that testosterone may dial down the immune system in humans is consistent with the results of studies of other animals, ranging from fish to chimps.

For more details on the study and why high testosterone may provide a less obvious evolutionary advantage, read this December Scope post from my colleague Bruce Goldman.

Previously: In men, a high testosterone count can mean a low immune responseAdults’ immune systems “remember” microscopic monsters they’ve seen beforeImmunology escapes from the mouse trap and Immunology meets infotech
Photo by Iain Farrell

Infectious Disease, Pregnancy, Public Health, Women's Health

Text message reminders shown effective in boosting flu shot rates among pregnant women

Text message reminders shown effective in boosting flu shot rates among pregnant women

pregnant_textingInfluenza is now widespread in 35 states across the country. Changes to the immune system during pregnancy make expectant moms more susceptible to the flu, and these women also face a particularly high risk for complications if they get sick. But despite this, roughly half of pregnant women fail to get a seasonal flu shot.

In an effort to increase adherence rates among moms-to-be, Columbia University researchers recently examined the effectiveness of using text message reminders. Psych Central reports:

Women in the intervention group received five weekly text messages about the importance of the vaccine starting in mid-September 2011 and two text message appointment reminders.

Both the intervention group and a control group received standard automated telephone appointment reminders.

The results showed that text messaging was successfully used to increase vaccination coverage.

Adjusting for gestational age and number of clinic visits, women who received the intervention were 30 percent more likely to be vaccinated.

A subgroup of women early in the third trimester had the highest intervention effect – 61.9 percent of the intervention group was vaccinated versus 49 percent for the control group.

The study adds to a growing body of work that shows how mobile health initiatives can help improve public health.

Previously: Ask Stanford Med: Answers to your questions about seasonal influenza, Flu shots for moms may help prevent babies from being born too small and Examining the effectiveness of text4baby service
Photo by niXerKG

Evolution, Immunology, Infectious Disease, Men's Health, Research, Stanford News

In men, a high testosterone count can mean a low immune response

In men, a high testosterone count can mean a low immune response

alpha maleMen have deeper voices and tons more facial and body hair than women. They are (usually) bigger, stronger, and much more likely to risk their lives on a whim. I, for example, have been known to bite a full-sized salami in half with a single snap of my jaws when hungry, angry or threatened. Or just for the hell of it.

But when it comes to immune response, men are wimps. It’s well documented that, for reasons that aren’t clear, men are more susceptible to bacterial, viral, fungal and parasitic infection than women are and that men’s immune systems don’t respond as strongly as women’s to vaccinations against influenza, yellow fever, measles, hepatitis and many other infectious diseases.

A new study just published in the Proceedings of the National Academy of Sciences by immunologist Mark Davis, PhD, who directs Stanford’s Institute for Immunity, Transplantation and Infection, and his colleagues may explain why. The same steroid hormone that makes a man’s beard, bones and muscles grow operates – albeit it in a slightly indirect way – to shrink immune responsiveness. Yep, we’re talking about (sigh…) that much-maligned male molecule, testosterone. In a nutshell, high circulating testosterone levels boost the activity of a clutch of genes that, among other things, dial down the aggressiveness with which our immune systems fight back against invading pathogens.

Now why, we ask ourselves, would evolution be so perverse as to have designed a hormone that on the one hand enhances classic male secondary sexual characteristics such as muscle strength, beard growth (or antler size, as the case may be) and risk-taking propensity – the very hallmarks of the alpha male – but on the other hand wussifies men’s immune systems?

Here’s what I got from talking at length (and, I admit, in an uncharacteristically high-pitched voice) to Davis in preparation for the news release I wrote about the study:

The evolutionary selection pressure for male characteristics ranging from peacocks’ plumage to deer’s antlers to fighter pilots’ heroism is pretty obvious: Females, especially at mating-cycle peaks, prefer males with prodigious testosterone-driven traits. Davis speculates that high testosterone may provide another, less obvious evolutionary advantage… Men are prone to suffer wounds from their competitive encounters, not to mention from their traditional roles in hunting, defending kin and hauling things around, increasing their infection risk. While it’s good to have a decent immune response to pathogens, an overreaction to them — as occurs in highly virulent influenza strains, SARS, dengue and many other diseases — can be more damaging than the pathogen itself. Women, with their robust immune responses, are twice as susceptible as men to death from the systemic inflammatory overdrive called sepsis. So perhaps, Davis suggests, having a somewhat weakened (but not too weak) immune system can prove more lifesaving than life-threatening for a dominant male in the prime of life.

Previously: Best thing since sliced bread? A (potential) new diagnostic for celiac disease, Deja Vu: Adults’ immune systems “remember” microscopic monsters they’ve seen before, Immunology escapes from the mouse trap and Immunology meets infotech
Photo by Craig Sunter *Click-64*

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