June 2010

Marburg virus, like its fellow filovirus Ebola, causes hemorrhagic fever and high death rates among humans. Also like Ebola, the virus is considered a potential bioweapon and has no known treatment or cure post-infection.

Developing a vaccine capable of providing protection against diseases like Ebola and Marburg after exposure has become a priority in light of known laboratory accidents and hypothetical first-responder scenarios. In 2009, a Hamburg scientist working with Ebola-Zaire accidentally pricked herself with a contaminated needle, setting off panicked global attempts by researchers to help her. Eventually the woman, a virologist from the Bernard Nocht Institute for Tropical Medicine, was given an experimental Ebola vaccine that had shown promise in preventing infection in monkeys when given post-exposure. She never developed the disease, although it’s not known whether the vaccine protected her from it. Prior to the Hamburg case, the previous known exposure was in 2004, in a U.S. Army researcher at Fort Detrick, Maryland.

These cases, in addition to hypothetical scenarios in which first responders may be exposed to filoviruses–coupled with the fact that no known treatment exists–have prompted efforts to further develop and test post-exposure vaccines. More

Smallpox, HIV, influenza: the names of these pathogens usually induce fear. Smallpox, although it has been eradicated for 30 years, killed millions in its time; HIV, a relative newcomer to the human race that appeared just a few years after smallpox was eradicated, infects 7,400 people each day. Influenza presents its own unique challenges with its tendency toward frequent genetic change, requiring new seasonal flu vaccines each year and sometimes surprising us with unexpected new strains.

Artist Luke Jerram examines these and other pathogens in Infectious Beauty, an exhibit of “glass microbiology” at the Heller Gallery in New York.  In creating these pieces, according to his website, Jerram explores “the tension between the artworks’ beauty, what they represent and their impact on humanity. ”

Jerram consulted with virologists before designing the sculptures, which were then created by professional glassblowers. His motivation stemmed partly from dissatisfaction with the way viruses and bacteria are typically portrayed: in color, even though the electron microscope photos usually used to capture them are black and white. Jerram, who is partially colorblind, considered how artificial coloring of these pathogens affected viewers’ understanding of them. More

Though not well known in the United States, Rift Valley fever (RVF) is a dangerous viral disease that is a major cause for concern in Africa. RVF primarily affects animals and can infect several species, including cattle, sheep, goats and camels. Protecting animals from the virus is extremely important in farming, as it has a high death rate for some animals of a particular age (up to 90% for lambs) and can cause a near-100% abortion rate among pregnant ewes. These losses can be devastating for those who raise livestock.

Rift Valley fever is also a concern, however, because it can sometimes infect humans. This typically occurs through contact with infected animals, but the virus can also be spread by the bite of infected mosquitoes or blood-feeding flies. Some evidence suggests that humans can even be infected by drinking unpasteurized or uncooked milk from infected animals.

Typically a human infection with RVF is mild and passes without treatment, but there are three more serious forms of the disease: one that leads to retinal lesions (and possible blindness); one that leads to meningoencephalitis and leaves the victim vulnerable to residual neurological problems; and one that leads to haemorrhagic fever, with a death rate as high as 50%. Prior to 1997 the disease had been limited to Sub-Saharan regions, but outbreaks have since occurred in Saudi Arabia, Mauritania, Egypt and Yemen, and outbreaks in Kenya, Somalia and Tanzania from 2006-2007 led to human deaths, raising concern that the virus could continue to spread. The United States federal government has also classified RVF as a potential biowarfare threat. More

International Health Regulations allow countries at risk for yellow fever transmission to request certificates of vaccination from foreign travelers. If a visitor is coming from a country considered “high risk” for the disease, they must present a yellow fever certificate approved by the World Health Organization–sometimes at the port of entry, and sometimes before they can even obtain a travel visa.

These policies have no doubt prevented yellow fever transmission, but vaccine shortages in Uganda combined with yellow fever health regulations have led to headaches for some World Cup fans. Uganda’s South African mission, where visas are issued for Ugandans traveling to the World Cup, can’t issue those visas without yellow fever certificates–and many would-be travelers don’t have the certificates, because they haven’t been able to get the vaccine.

CNN’s Samson Ntale reported on June 17 that the large number of travelers headed for South Africa during the World Cup exacerbated the Ugandan vaccine shortage. Ntale reported that more yellow fever vaccine has been ordered, but that in the meantime, many Ugandans have been first traveling to other countries to get their vaccinations and certificates, including Kenya and Tanzania. More

It can be difficult to explain to a two-year-old that the scary-looking needle headed for her arm will actually help keep her healthy. To a young child, “I’m giving you a vaccine to protect you from the measles” often sounds more like, “I’m going to jab you with a pointy object.” Childhood vaccinations come with their share of pain and crying.

In a review published in Archives of Disease in Childhood (A BMJ journal), Denise Harrison and co-authors report that feeding sugar solutions to children during or after vaccinations can reduce the incidence and duration of crying, as well as pain.

Previous research had established that sugar solutions could reduce pain associated with vaccination in newborn children–a key finding, since the first dose of Hepatitis B vaccine is recommended before newborns are discharged from the hospital. However, beyond one month of age, the evidence was not conclusive. Harrison and her colleagues set out to compare the effects of sugar solutions to that of water, as well as no treatment, in children 1-12 months old–a period of time during which it’s recommended they receive Hepatitis B, rotavirus, DTaP, Hib, pneumococcal, and polio vaccines. More

The Historical Medical Library here at The College of Physicians of Philadelphia holds seven floors of stacks of books, journals, and archives. The scale of the library, and its testament to human illness, can be overwhelming. Our recent research on tuberculosis provides an example: standing in the stacks, surrounded by row upon row of books about TB, is a grim experience. But though our library gives the impression that TB is an historical artifact, it’s most certainly not. It continues to take an enormous global toll: there are 9.4 million new infections a year, and there were 1.3 million deaths from TB in 2008 alone.

One of these recent trips into the stacks led us to the Final Report of the International Tuberculosis Campaign (1951), an optimistic portrait of the promises of an early immunization campaign. The book offers comprehensive statistics of the massive tuberculosis campaign undertaken in 23 countries in the late 1940s and early 1950s.

The project initially began as a Scandinavian Red Cross effort in Europe in the aftermath of World War II. Tuberculosis rates had soared in the disruption and privation the war created. In Poland, tuberculosis rates among children had quadrupled. As Niels Brimnes writes, the president of the Danish Red Cross announced on the radio in 1948, “The spirit of the Nordic Vikings has been part of this campaign as in the old days. Earlier we went out sword in hand to conquer and fight each other. Today we go out together with the needles as our only weapon to fight the scourge of the Second World War: tuberculosis” (Niels Brimnes, “Vikings against Tuberculosis: The International Tuberculosis Campaign in India”). More

One of the main challenges presented by influenza is the virus’s tendency to undergo genetic change. Seasonal influenza virus strains change frequently and, as a result, new vaccines are needed each year to provide protection against the new strains. That’s problematic for two reasons, however: first, it takes time to develop new vaccines, even though the techniques and procedures for doing so are well-established; and second, even after a vaccine is developed and mass-produced, it still has to be distributed and administered to millions of people. Both of these steps require a lot of time, an efficient infrastructure, and a large, coordinated effort to achieve.

In response, researchers are trying to develop an influenza vaccine that can provide broad protection against influenza–including future strains–so that a single vaccination would be enough to protect an individual from the seasonal flu for three, five, perhaps even ten years or more.

Past influenza vaccines have targeted a particular segment of the hemagglutinin (HA) protein that allows influenza viruses to attach to and enter cells. (There are many different hemagglutinin subtypes; avian flu, for example–H5N1–is of hemagglutinin subtype 5, while the novel H1N1 “swine flu” is of type 1.) To this point, flu vaccines have focused on the “globular head” of the HA protein, the part of its structure most frequently targeted by antibodies to influenza. Unfortunately the globular head, like influenza viruses as a whole, is subject to frequent genetic changes–so researchers are focusing on a different part of the HA protein’s structure. More

Ebolavirus, also known simply as Ebola, gained notoriety in the United States in 1989 and 1990, when imported monkeys infected with a subtype of the virus were introduced to quarantine facilities in Virginia, Pennsylvania, and Texas. The viral species isolated from the infected monkeys at a Reston, Virginia lab was eventually named Ebola-Reston, and the incident was documented in Richard Preston’s best-selling 1994 book The Hot Zone. Yet while Ebola-Reston proved quite dangerous to monkeys, it did not cause illness in humans: though some humans exposed to it developed antibodies, none experienced any symptoms.

Other species of Ebola, however, are far more dangerous. Ebola-Reston is only one of five known species of Ebola, and is the only one of the five that has never caused serious human illness. Of the others–Ebola-Zaire, Ebola-Sudan, Ebola-Ivory Coast, and Ebola-Bundibugyo–all but Ebola-Ivory Coast have led to varying rates of fatalities since the first known outbreak of Ebola-Zaire killed 88% of infected patients in 1976. More

*Update* -- Note that the Advisory Committee on Immunization Practices voted on October 27, 2010, for new recommendations regarding Tdap vaccination. For more information, see our blog post "Advisory Committee Votes for Expanded Pertussis Vaccine Recommendations." -- HOV StaffGuest Post by Andreas Bollmann, MD, PhD, FAAP Pediatric Associates Inc.

Since December 2006, the Advisory Committee on Immunization Practices (ACIP) has recommended the use of Tdap (tetanus and diphtheria toxoids, acellular pertussis vaccine) instead of Td (tetanus and diphtheria toxoid immunization) during adolescence and at least once during adulthood.

Most adults don’t worry about whooping cough (also known as pertussis). Once a patient has moved on from a pediatrician’s care, this disease usually falls off everybody’s radar.

In fact, vaccination rates among adults in the United States against pertussis are estimated to be very low.

Studies show that about 75% of pertussis infections among babies are contracted from household members. Pertussis cases reported from 2000 to 2003 have risen (and it is likely they are even higher, since only a small percentage of cases are actually reported). From 2000-2004, 92 deaths occurred in infants (12 month of age and younger) in the United States. From 2004-2005, 66 deaths occurred. And just recently, California health officials reported that pertussis cases so far in 2010 have more than doubled from the same period in 2009. Already this year in California, four infants have died from the disease. More