Value for money
Pneumonia, which is most often caused by infection with Streptococcus pneumoniae, causes approximately two million child deaths annually, mainly in developing countries. A pneumococcal conjugate vaccine is available, but would routine vaccination efforts be cost-effective? Publishing in the Lancet, an analysis of published and unpublished data on the efficacy of the pneumococcal conjugate vaccine was undertaken to determine if vaccination would be cost-effective in 72 of the world's poorest countries. They concluded that if a US$5 vaccine shot reached every child in these countries, up to 407, 000 deaths per year would be prevented and 8.34 million disability-adjusted life years would be averted. At this price, vaccination would be extremely cost-effective in 68 out of 72 developing countries. Lancet
DCs for HIV vaccine?
Many scientists believe that to be effective, an HIV vaccine must stimulate an efficient killer (CD8+) T-cell response, as killer T cells can clear virus-infected cells, mediate resistance to HIV and produce antiviral signalling molecules. Vaccines that have been designed to stimulate T-cell responses so far though are not very effective.
One way around this problem might be to target dendritic cells (DCs), which are specialized antigen-presenting cells that can cross-present antigens to T cells. Ralph Steinman's group targeted fragments of the main HIV protein Gag to DCs using a DC-specific monoclonal antibody. Using this method they induced DCs in the blood of HIV-infected individuals to stimulate a Gag-specific killer T-cell response. Other research in mice has shown that DCs can stimulate helper T cell and antibody responses too. The team hope that this encouraging preclinical evidence will lay the foundations for the development of a prototype vaccine for testing in humans. PNAS
Boost for vaccine coverage
New figures released by the World Economic Forum show that since the launch of the GAVI Alliance (formerly the Global Alliance for Vaccines and Immunization) the extra funding for vaccination has saved approximately 2.3 million lives. The GAVI Alliance is a public–private partnership that was set up to increase access to childhood vaccines in the world's poorest countries by philanthropist Bill Gates and his wife Melinda. The massive purchasing power of the GAVI Alliance, coupled with long-term contracts to buy vaccines, has led to huge price cuts. GAVI Alliance resources have enabled poor countries to introduce new vaccines, such as hepatitis B and yellow fever, and increase access to basic childhood vaccines, such as polio, diphtheria, tetanus, pertussis and measles. In Africa, 73% of children are now immunized against common childhood diseases. Reuters
Improved SARS model
In order to find new antiviral drugs and test vaccine candidates for SARS (severe acute respiratory syndrome) a good animal model that recapitulates human pathogenesis and symptoms is a prerequisite. But mouse models in current use by SARS researchers do not satisfy these criteria, as young infected mice do not develop full-blown disease and while older mice do suffer symptoms, immune problems complicate analyses. A team led by Kanta Subbarao passaged SARS-CoV (Urbani strain) in the lungs of young BalbC mice and after 15 passages a virus (MA15) lethal for mice was produced by adaptation. Mice infected with MA15 intranasally die from an overwhelming viral infection with pulmonary pathology that faithfully mimics SARS-CoV disease in humans — a far better model. PloS Pathogens
Portable biosensor for 'flu
A biosensor has been developed that can detect avian H5N1 influenza from cloacal or tracheal swabs of birds in less than 30 minutes. H5N1 influenza has infected more than 260 people and killed 163 of them since 2003. The main advantage of this biosensor is that it is portable. Being able to track the spread of epidemic viruses quickly could inform rapid response teams in real time.
The biosensor prototype, designed by a team that included Yanbin Li (bioengineer), Steve Tung (mechanical engineer), Luc Berghman (immunologist) and Billy Hargis (poultry scientist), uses magnetic bio-nanobeads, a microfluidic biochip and red blood cell complexes to detect the virus. Specific monoclonal antibodies to different subtypes of avian influenza viruses are being developed to increase the range of influenza viruses detected. The device could be ready for commercial production within a year, and would probably cost less than US$8,000 with each sample tested at a cost of approximately $10. Newswise
HIV microbicide hope
Using microbicides to combat HIV could prove a cheap and effective preventative measure. Vulnerable women often cannot ask men to use condoms owing to cultural taboos, but these gels could empower women to protect themselves against the deadly virus. First-generation microbicides are currently undergoing clinical trials and are expected to be on the market in 4 years. These gels can be 50–60% effective but a new algae-based gel being tested in Brazil could be substantially more effective. First phase testing of the compound — dolabelane diterpene — which is derived from Dictyota pfaffii, a species found on the Brazilian coast, has shown that it reduced replication of HIV by 95% in cell culture. Roger Pebody (Terence Higgins Trust) commented that 'microbicides look set to be the best new prevention technology for vulnerable women in the hardest hit countries of central and southern Africa'. Phase II tests are starting now and lead researcher Luiz Castello Branco hopes that the gel will be on the market in seven years. SciDevNet , BBC
5-in-1 jab gains US approval
Pentacel, a Sanofi Pasteur vaccine, has been declared safe and effective by US Federal health advisors, making approval by the US Food and Drug administration more likely. The vaccine, which targets tetanus, diphtheria, whooping cough, polio and Haemophilus influenzae type B, has been sold in Canada since 1997, and is available worldwide in nine countries. More than 12.5 million doses of Pentacel vaccine have been administered in Canada. The main advantage of this multiple vaccine is that it reduces the number of injections that infants receive. Washington Post
Never too late for Ebola
Ebola outbreaks have increased in frequency over recent years but are usually self-contained owing to the severity of the disease — those infected often die before they can pass the virus on. The outlook following infection with the virus is grim. Ebola is one of the worlds' most virulent viruses, and the haemorrhagic fever that accompanies infection is lethal in 50–90% of cases. Although vaccines protect primates, a human vaccine is not yet available. In the absence of any effective drug treatments, a prototype vesicular stomatitis virus-based vaccine that protects mice and monkeys against Ebola, was tested as a post-exposure treatment. Fifty percent of guinea pigs and 100% of mice survived when the vaccine was administered a full day after exposure to Ebola. Even Macaque monkeys were protected, with 50% survival rates when vaccinated 30 minutes post-exposure. This offers promise for anyone infected accidentally in the laboratory, or during an outbreak. PloS Pathogens
Animal disease action plan in China
The Chinese government has pledged to spend more than US$1.1 billion in an ambitious plan to bring severe animal disease under control by 2015. Part of the plan includes setting up an animal epidemic prevention system by next year that will coordinate animal disease control and will include 2,293 prevention centres located throughout all 31 Chinese provinces. Other local facilities will include more than 18, 000 new veterinary surgeries and stations in nature reserves that will monitor the health of wild animals. Four national laboratories for identification and analysis of diseases including avian influenza and foot and mouth disease are also planned. Part of the impetus for this scheme might be the vast economic losses in China due to avian influenza outbreaks in poultry, which have cost Chinese farmers alone US$1.02 billion. SciDevNet
Group B strep in Malawi
Group B Streptococcus (GBS) is a leading cause of neonatal illness and death in industrialized nations but, until recently, it was not thought to be a problem in the developing world. Now, Stephen Graham and colleagues report that GBS is a prominent cause of neonatal sepsis in Africa after all. The research shows that the pattern of neonatal GBS diseases in Malawi is similar to that found in industrialized countries, except that outcomes for infants are markedly worse. Vaginal disinfection using chlorhexidine wipes during labour, in studies that were actually designed to reduce HIV transmission, markedly reduced maternal sepsis-related deaths. But the researchers caution that disinfection is unlikely to happen during unassisted deliveries. They recommend that vaccination, which has fallen off the public health agenda owing to successful GBS prophylaxis with antibiotics in developed countries, should be considered to tackle this problem. Emerg. Infect. Dis.
Bird 'flu in the UK
The first outbreak of the H5N1 influenza strain in domestic poultry has been reported in the UK, at a farm run by Bernard Matthews, the biggest turkey producer in Europe. The first turkey died on Tuesday 30 January. Following identification of the H5N1 strain, almost 159, 000 birds have been gassed as part of a Department for the Environment, Food and Rural Affairs action plan to contain the virus. Initially, wild birds were blamed for the outbreak, but there are no wildfowl migration patterns that could account for this infection. The virus has so far been detected in only one shed out of 22 at the farm, and 320 of the 2,000 staff have been given the Tamiflu anti-viral drug. Last month thousands of geese were culled at a farm in Hungary following a H5N1 outbreak, which contained the disease. Farmers in Norway have been ordered to keep flocks indoors as a precautionary measure. BBC,
Reuters
Outbreak news
Avian influenza. A 6 year-old girl from the Central Java province in Indonesia died after contracting avian influenza on Friday 19 January, bringing confirmed deaths from influenza in Indonesia to 63, the most of any country so far. In Nigeria, a 22-year old woman died from suspected avian influenza on Tuesday 16 January, but this case has yet to be confirmed by the WHO. WHO
Rift Valley fever. A CDC spokesman announced that an outbreak of Rift Valley fever in Kenya, which has killed 150 people according to the Kenyan government, might be slowing down. The disease is mainly caught from slaughtered cattle. Neighbouring countries are thought to be at risk, and the outbreak has already spread to Somalia. Reuters
Cholera. A cholera outbreak has been reported in the port city of Pointe-Noire in the Republic of Congo. Pointe-Noire is the economic hub of the country and the second largest city with an estimated population of 800,000. Three treatment centres offering free care have been set up by the government. Reuters
In the News was compiled with the assistance of David Ojcius, University of California, Merced, USA. David's links to infectious disease news stories can be accessed on Connotea ( http://www.connotea.org ), under the username ojcius.