From Science Buzz: Hit 'em with your best shot(s)

We're back in business here at the Science Museum (although the building is still closed to the public until next Friday), just in time to report some good news.

Ouch: Taking one for the team?
Courtesy Spamily

The CDC reported yesterday that 77.4% of US children between the ages of 19 months and three years received all their recommended vaccinations in 2007. That's a slight improvement over the 2006 statistic. There are big regional variations in coverage, and children living below the poverty line are slightly less likely to be fully vaccinated, but overall less than 1% of US kids received no immunizations at all.

What are the recommended shots?

• Four or more doses of diphtheria, tetanus toxoid, and any acellular pertussis vaccine, or DTaP
• Three or more doses of polio vaccine
• At least one dose of measles, mumps, and rubella (MMR) vaccine
• At least three doses of Haemophilus influenzae type b vaccine
• At least three doses of hepatitis B vaccine
• At least one dose of varicella vaccine

Some folks don't vaccinate their kids--particularly against measles, mumps, and rubella (MMR)--because they worry that the vaccine is linked to autism. That theory has been debunked many times, in many countries, but it persists. On Wednesday, researchers from Columbia University and the CDC offered up another study showing zero causal relationship between the MMR vaccine and autism (or gastrointestinal problems.) So kids, roll up your sleeves at those back-to-school physicals and get your shots. It sucks, but it beats getting measles.

On the other hand, evidence is mounting to show that flu shots don't work well to protect people over 70. Older people have a lesser immune response to the vaccine and don't develop as much immunity. But the very old and the very young also account for the highest number of flu deaths. So what to do? According to the NT Times article:

"Dr. Simonsen, the epidemiologist at George Washington, said the new research made common-sense infection-control measures — like avoiding other sick people and frequent hand washing — more important than ever. Still, she added, “The vaccine is still important. Thirty percent protection is better than zero percent.”

Another way to protect the elderly is to vaccinate preschoolers. Not only are they likely to pick up the flu before other members of the family, but there's some evidence that preschoolers are actually the drivers of annual influenza outbreaks. Stop the flu in young kids, and you might just stop it for everyone else, too.

From Science Buzz: New 1918 influenza findings

This week two new findings were published about the 1918 influenza pandemic. The first looked at preserved lung tissue from soldiers that died from the pandemic. They examined 58 samples and found that in most cases the predominant disease at the time of death appeared to have been bacterial pneumonia. It is hypothesized that influenza virus damaged the cells of the tissue lining the lung allowing the bacteria to invade and eventually led to death of the host. The authors of the study concluded:

“if severe pandemic influenza is largely a problem of viral-bacterial copathogenesis [double infection], pandemic planning needs to go beyond addressing the viral cause alone (e.g., influenza vaccines and antiviral drugs). Prevention, diagnosis, prophylaxis, and treatment of secondary bacterial pneumonia, as well as stockpiling of antibiotics and bacterial vaccines, should also be high priorities for pandemic planning.”

Click here to read the original scientific article in the Journal of Infectious Disease or here to read a ScienceDaily news report

The second finding examined if people that survived the flu had antibodies against the 1918 influenza pandemic in their body. The researchers collected blood samples from 32 survivors age 91-101 years and found that all reacted to the 1918 virus, suggesting that they still possessed antibodies to the virus. One of the researchers, Dr. James Crowe Jr., stated

"The B cells have been waiting for at least 60 years – if not 90 years – for that flu to come around again. That's amazing…because it's the longest memory anyone's ever demonstrated."

The research team went on to see if the antibody protected against the 1918 strain of influenza by infecting mice with the influenza. Some had been treated with the antibodies – others had not. They found that the mice receiving the highest dose of antibodies survived and the others died. For a well written summary of the research in ScienceDaily click here.

From Science Buzz: Let's hear it for maggots!

Researchers at Swansea University, in the UK, are developing an antibiotic that can fight the MRSA superbug. And they're using superbugs to do it. OK, not superbugs. They're using the secretions from the maggots of the common green bottle fly.

A cage match I'm not sure I want to see: Maggots secrete a compound that can fight superbugs, including 12 strains of MRSA, E. coli, and C. difficile.
Courtesy National Institutes of Health

Super gross? Sure. And you won't see an ad for this antibiotic (Seraticin) on TV anytime soon. It takes some 20 maggots to make a single drop of the drug. So scientists have to fully identify it, figure out a way to synthesize it in the lab, test it on human cells, and put it through a clinical trial.

In the meantime, using live maggots on infected wounds is a time-tested way of beating infections. Dr. Alun Morgan, of ZooBiotic Ltd, told the BBC,

"Maggots are great little multitaskers. They produce enzymes that clean wounds, they make a wound more alkaline which may slow bacterial growth and finally they produce a range of antibacterial chemicals that stop the bacteria growing."

How effective are maggots? The University of Manchester has been doing research on diabetic patients with MRSA-contaminated foot ulcers. The patients treated with maggots were mostly cured within three weeks. Patients who got more conventional treatment needed 28 weeks.

So give maggots a big shout out. And then check these other stories:
"NHS 'needs to use more maggots'"
Prescription insects
Fun with beetles

From Science Buzz: One step closer to a malaria vaccine

Next year, researchers plan to start small-scale human trials of a malaria vaccine that's proven 75-80% successful in mice.

From Science Buzz: HIV transmissions are hard to estimate

Researchers at the International AIDS Conference sifted through published papers on the risk of heterosexual HIV transmission. They say that while a popular estimate pegs the rate of HIV transmission through heterosexual sex at 1 per 1000 contacts, true rates of infectivity are all over the map and dependent on many variables. The infectivity rate for certain sorts of activities is much, much higher-- as high as 1 in 3 contacts. The take away message? "Claims in both the popular media and the peer-reviewed literature that HIV is very difficult to transmit heterosexually are dangerous in any context where the possibility of HIV exposure exists."