The Flu Vaccine

October 12, 2009

As new cases and concerns about seasonal flu and swine flu (H1N1) continue to spread worldwide, two vaccines have recently been made available. Both the nasal spray vaccine and injectable vaccine for seasonal flu have proven effective for specific portions of the population, however distribution is still slow. For the H1N1 (swine flu) virus, The Baltimore Sun reports, availability is still an issue and many areas have not yet received enough doses to meet the demand. While many in the developed world do not yet have access to the H1N1 vaccine, Dr. Bernadine Healy notes that the problem is even greater in the developing world. To help these nations fight the pandemic, the United States has agreed to donate 10 percent of its vaccination supply to the World Health Organization (WHO) – eight other nations will make similar donations.

Fantastic Image by Deborah Ervin

Inoculating individuals for both viruses is complicated by the time frame in which the vaccinations can occur. If one chooses nasal spray for both seasonal and swine flu, they must wait four weeks between doses, while if one is injected for one virus and uses nasal spray for the other, they can be administered together. Discovery Health reports that doctors recommend annual flu shots to lessen the chances of becoming ill. Individuals as young as six months can be inoculated, according to the Centers for Disease Control and Prevention (CDC) and side effects are reported to be minor. Because the virus used to make the seasonal flu vaccine is dead, it is not possible to contract flu from a flu shot, however one may expect a low-grade fever 8 to 24 hours following injection, a swollen or tender area around the injection site, a slight headache or chills within 24 hours.

The seasonal flu shot is an inactivated vaccine, and contains three influenza viruses – one A(H3N2) virus, one regular seasonal A(H1N1) virus (which differs from the 2009 H1N1 virus), and one B virus. The viruses used change annually based on international surveillance which track infection trends and scientists estimations about which strains will circulate during the year. In contrast to the flu shot, the nasal-spray flu vaccine contains a weakened but still living flu virus, sometimes called LAIV (live attenuated influenza vaccine). These nasal mists are approved for use in healthy individuals ages two to 49 who are not pregnant. In addition to nasal sprays, Discovery Health reports that researchers at Stanford University and the University of Alabama at Birmingham have been working with naked DNA in an effort to develop a vaccine that could be delivered via shampoo or dermal patch.

Three recent large-scale studies, including a study led by Dr. Arnold S. Monto of the University of Michigan, indicate that while the seasonal flu shot is more effective for adults and safe for women who are pregnant, the intranasal vaccine (nasal spray) is more effective at preventing flu in children. These studies showed 35 to 53 percent fewer cases of flu in children who were given the nasal spray vaccine than those who received injected vaccines. The Los Angeles Times reports that injectable vaccines prevent roughly 50 percent more seasonal flu in healthy adults than the nasal spray vaccines.

Due to the relative newness of the H1N1 vaccine, health authorities have implemented a number of tracking measures to ensure its safety. The Associated Press reports that Harvard Medical School scientists are working to link insurance databases covering 50 million people with vaccination registries to allow them to determine if people visit a doctor after being vaccination as well as the reason for the visit. Johns Hopkins University and the CDC are also working to ensure that any side effects are noted and addressed quickly. These efforts include emailing individuals who have been vaccinated recently to see how they are feeling (Johns Hopkins), and preparing take-home cards asking vaccine recipients to report any side effects to the nation’s Vaccine Adverse Event Reporting system (CDC). These measures are being undertaken as in the Internet-age, the Associated Press notes, one person updating their Facebook status to say that they got a flu shot and feel sick could cause a wave of similar reports.

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Associated Press on the Nasal Spray Flu VaccineThe New York Times on CDC Side Effect Tracking Measures


A Killer in the Developing World

August 17, 2009

HIV/AIDS and malaria are major health concerns worldwide, however the World Health Organization (WHO) reports across much of Asia and Africa secretory diarrhea – which accounts for 1.6 million deaths annually – is an even greater threat. Each day in India, diarrhea-related diseases kill 1,250 people, only slightly fewer than the H1N1 virus has killed globally to date (1,500), according to the WHO. Caused by E.coli, cholera, and other bacteria, viruses, or parasites, diarrhea affects individuals more often in areas that lack safe water and appropriate sanitation. In individuals with secretory diarrhea, infectious agents cause too much water to enter the bowel and be evacuated from the body, leading to excessive dehydration and eventually death if appropriate treatment is not received.

Diarrhea in the Developing World
In nations of the developing world, including Bangladesh, India, Mali, and Pakistan, aid organizations and government agencies have begun distributing zinc supplements to villagers as a treatment for diarrhea. Data from recent studies documented in the August 2009 issue of the Journal of Leukocyte Biology suggest that zinc may help to activate the T-cells needed to destroy viruses and bacteria, including those that cause diarrhea. Time Magazine reports that in tablet or liquid form, zinc can be used in combination with oral-rehydration therapy (ORT). While it is not entirely clear how zinc helps halt diarrhea, Oliver Fontaine, a diarrhea specialist for the WHO, explains that a single course of zinc treatment can stave off diarrhea for three months.

Unlike zinc, which often produces an immediate improvement in an individual’s health, the glucose present in ORT (a solution of sugars and salts) slows the evacuation of fluids allowing for the absorption of electrolytes in the intestines, and halting the progression of dehydration to a chronic state. Because of the delay in the improvement of symptoms with ORT, “Mothers don’t see ORT as real treatment,” according to Eric Swedberg, senior director of health and nutrition at Save the Children U.S. Though ORT is an effective treatment for diarrhea, only about 35 percent of families in diarrhea-stricken countries utilize the method.

By offering zinc in combination with ORT, government-run programs in Ethiopia and Tanzania hope to increase the number of people surviving diarrheal outbreaks. Additionally, efforts are being made in Mali to add zinc to the country’s list of essential drugs, a step towards improving the distribution of the tablets. To halt the recent outbreaks of diarrhea in Nepal that have led to 235 deaths to date, the Office of the Prime Minister has begun coordinating efforts to construct a toilet in each household, provide sources of potable water, and improve waste disposal systems. In addition, the Nepali government has mobilized 298 personnel to aid in providing treatment in the area through 89 health camps.

To support these and other similar efforts, funding for the provision of the potentially life-saving drugs, and awareness of their effectiveness must be increased. In 2007, only four percent of all U.S. funding for research of epidemics in the developing world was devoted to finding solutions to decreasing the number of diarrhea-related deaths. Support from organizations like the Bill and Melinda Gates Foundation have provided some support, but additional funding is still needed not only to ensure that zinc tablets are more widely distributed, but also to assist in efforts to improve the quality of available water and waste treatment measures.

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WHO on Water Treatment and Safe StorageOn Diarrhea and Tuberculosis in IndiaTime Magazine on Zinc to Treat DiarrheaDiarrheal Deaths in NepalOn Zinc Fighting Infection


Air Travel and Disease

July 7, 2009

As the number of cases of influenza A(H1N1) (“swine flu”) continue to rise, researchers are seeking solutions to slow the spread of the virus. A recent report from CNN indicated that the World Health Organization (WHO) has recorded 29,669 cases and 145 deaths in 74 countries. The virus has been categorized as a phase 6 “moderate pandemic” by the WHO, meaning that most individuals who are infected will recover. However, amidst recent reports of mothers bringing their children to “swine flu parties” to expose them to the virus (a practice that the British Medical Association has spoken out against), an individual has presented with drug-resistant swine flu. Efforts to create effective vaccines are ongoing, as are alternative means of tracking and slowing the spread of the virus.

Air Travel and Disease

A group of Canadian researchers have analyzed the correlation of the spread of the disease (specifically focusing on influenza virus A (H1N1)) and air travel patterns. The project, known as BioDiaspora, tracks the movements of 2.2 billion airline passengers annually which can then be used to map the possible and probable spread of disease. As reported in the New England Journal of Medicine, the researchers gathered data from the International Air Transport Association (IATA) from the period between March and April 2008. Information about a total of 2.35 million passengers who flew from Mexico to 1,018 cities in 164 countries was mapped and compared to the spread of A(H1N1) to date. According to Dr. Kamran Khan, preliminary data indicated “If you had fewer than 1,400 arrivals from Mexico, you had only a 7 percent chance of getting an imported case.” In countries with more than 1,400 arrivals, the chance of infection in the area increased to 92 percent.

By tracking the spread of outbreaks of disease and comparing them with air travel patterns, researchers can predict which regions are at the highest risk of early infection. According to Dr. Michael Gardam, director of infectious disease prevention and control for the Ontario Agency for Health Protection and Promotion, disease-tracking tools may prove invaluable when dealing with outbreaks of infectious diseases, particularly those with short incubation periods. With this information, it will be possible to inform physicians in potential hotbeds of infection about how to identify a given disease, and ensure that vaccines are prepared and available in order to help stop the spread.

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WHO Information on PandemicsCNN Report on A(H1N1)New England Journal of Medicine on BioDiaspora