DNA Vaccine Techniques Show Promise Against Rift Valley Fever

Magnified approximately 34,000x, this transmission electron micrograph (TEM) depicted a tissue section that had been infected wi 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

Vaccine Shortage Delays World Cup Travel

A female Aedes aegypti mosquito flies off after feeding. This day-biting mosquito is the vector for yellow fever. CDC/ James Gat 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

Posted in:

A Spoonful of Sugar to Sweeten Vaccines’ Sting

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

Encouraging Results for Universal Influenza Vaccine

This illustration provides a 3D graphical representation of a generic influenza virion’s ultrastructure. A portion of the virion 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

Experimental Vaccine Protects Against Multiple Ebolavirus Species

Created by CDC microbiologist Cynthia Goldsmith, this colorized transmission electron micrograph (TEM) revealed some of the ultr 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

Recommendations on Pertussis (Whooping Cough) Vaccination for Adolescents and Adults

Scanning electron microscope image of Bordetella pertussis. Copyright Dennis Kunkel Microscopy, Inc. *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

HoV Staff Attend Congressional Briefing on HIV, TB, and Malaria Vaccine Research

Architect of the Capitol On Monday, May 17, staff from the History of Vaccines project traveled to Washington, D.C. to attend “New Promise in the Search for HIV, TB and Malaria Vaccines,” a joint briefing held on the 30th anniversary of the eradication of smallpox.

In their opening remarks, Dr. Alan Bernstein (Global HIV Vaccine Enterprise), Dr. R. Gordon Douglas, Jr. (Aeras Global TB Vaccine Foundation) and Colonel Chris Ockenhouse (U.S. Military Malaria Vaccine Program, Walter Reed Army Institute of Research) all stressed the need for continued efforts toward vaccines for malaria, HIV, and TB. They also highlighted the overlap between the incidence of the three diseases, as well as the interaction between them: Douglas specifically stressed the importance of developing a TB vaccine that can be used in HIV-positive individuals.

We at the History of Vaccines project were happy to provide material for the keynote talk by Dr. Gregory Poland (Vaccine Research Group, Mayo Clinic). Dr. Poland discussed historical and contemporary challenges in vaccine development and deployment, including political agendas and the threat of diseases as bioweapons post-eradication. More

Vaccine for Shingles Well-Tolerated, But Not Well-Accepted

Most people view chickenpox as a disease of childhood–or, as the vaccine against it is increasingly used, as a disease of the past. But varicella zoster, the herpes virus that causes chickenpox, is sneaky. Even after a varicella infection clears, the virus hides in the nerve cells, inactive. In about 20% of people who have had chickenpox, the virus will reappear later in life to cause shingles, a disease of severe pain and blisters on the body or face. Blisters on the face can cause problems with vision and hearing, while the spread of the disease to the body’s internal organs can cause serious damage, including encephalitis (inflammation in the brain).

A vaccine against shingles was approved by the U.S. Food and Drug Administration in 2006 after it was shown to be effective (in clinical trials, the vaccine reduced the risk of shingles by 50%). Recently, a long-term follow-up study of 38,000 participants from the trial that led to its approval also demonstrated its long-term safety. (The study, from the Annals of Internal Medicine, can be found here.)

The use of the vaccine, however, does not reflect the data on its safety or effectiveness: a separate study, also in the Annals of Internal Medicine, indicated that despite the vaccine being available since 2006 and recommended since 2008 by the Advisory Committee on Immunization Practices for all adults 60 or older, early use of the vaccine has been between only 2% and 7% in the United States. (That study can be found here.) More

FDA Approves Cancer Vaccine

The United States Food and Drug Administration (FDA) recently approved Dendreon Corporation’s “cancer vaccine,” Provenge, for the treatment of certain types of prostate cancer. It became the first cancer vaccine to be approved for use in the United States. (Gardasil, Merck’s HPV vaccine, is sometimes referred to as an anti-cancer vaccine since it prevents infection with strains of HPV that cause cervical cancer. Dendreon’s product, however, is designed to directly treat cancer.)

Provenge is not a vaccine in the same way we would think about vaccines against measles, polio, or other infectious diseases. Those vaccines are designed to prevent infection by priming the immune system against a particular pathogen: a strain of a virus is weakened or inactivated, for example, and a mass-produced vaccine is created that can be administered for future protection against that virus before it can take hold in the body.

Provenge, however, is designed to treat existing cases of advanced prostate cancer, not prevent cancer. It works in a similar way to what we think of as a typical vaccine: by priming a person’s immune system to attack the disease. Attacking cancer is complicated, however, since cancer cells are actually the body’s own cells, making it difficult to “teach” a person’s immune system to identify them. Provenge is designed to stimulate a T-cell response to prostate cancer cells that are present. More

Thirty Years of a Smallpox-Free World

A transmission electron micrograph of smallpox viruses using a negative stain technique. CDC/Dr. Fred Murphy In the not-so-distant past, smallpox was a scourge of mankind. It spread wildly through vulnerable populations, killing up to 30% of those it infected; those who survived were left scarred, some seriously disfigured or blind.

Smallpox ravaged the world’s population essentially unchecked for more than 3,000 years, sickening Egyptian pharaohs, British royalty, American presidents, and millions in between. But in the 1970s, the disease was nearing the end of its reign. Thanks to massive vaccination and surveillance efforts, smallpox became the first disease to be eradicated from the world. Today, we celebrate 30 years since the people of the world declared themselves free of its grasp.

The last stand

The final case of naturally occurring smallpox took place in Somalia in October of 1977, in a cook named Ali Maow Maalin. Personnel from the global eradication program immediately began efforts to find every individual Maalin had been in contact with, doing house-by-house searches and vaccinating anyone entering or leaving his town. By December 29, 1977, they completed a national search, and Maalin’s case proved to be the last. He survived. More