Wednesday, December 17, 2014

The FDA Approves a New Version of Gardasil

The FDA has approved a "new and improved" version of Gardasil, the controversial vaccine against Human Papillomavirus (HPV), the group of viruses that cause cervical cancer. The original Gardasil was effective against four types of HPV. The new version, called "Gardasil 9", is effective against those four types of HPV plus five more, for a total of nine.

Gardasil 9 is approved for use in both males and females. In males it is approved for prevention of anal cancer, and coincidentally it would also be effective in preventing the spread of HPV to females. Like the original Gardasil, Gardasil 9 is administered as a series of three shots.

Gardasil remains a controversial vaccine. Some people think that vaccinating young girls against a sexually transmitted virus will lead to promiscuity, even though the available suggests otherwise (see this Blog Oct. 21, 2012). There's also a rumor going around that Gardasil has caused the deaths of dozens of young women; that's not true, either, according to a leading rumor-checking site. The CDC, which collects reports of "adverse effects" on all drugs, continues to stress that Gardasil is safe.

Sunday, December 14, 2014

Does Platelet-Rich Plasma Therapy Work?

Great in theory, unproven in practice. It's been at least six years since Platelet-Rich Plasma Therapy (PRPT) was first proposed as a technique for speeding recovery from joint and connective tissue injuries, and we still don't know if it works!

In PRPT, a patient's own plasma is enriched in platelets by removal of blood cells and most of the water (see this blog Feb. 28, 2009). The remaining platelet-rich plasma is injected directly into the patient's injured joint or connective tissue. In theory, proteins and growth factors released by the platelets should speed the healing process. But do they?

The problem is that despite numerous clinical studies, the results are still inconsistent, according to an NPR article. Part of the problem is that in most studies the number of patients is relatively small (fewer than a hundred patients, rather than a thousand or more) and the techniques used and types of injuries treated vary. And since it's not yet proven to work, insurance companies don't pay for the procedure, meaning that the patient pays the total cost of roughly $600 to $1,500.

We should have known by now whether the technique works. We're still waiting....

Friday, December 12, 2014

An Outbreak of Mumps in the National Hockey League

About a dozen National Hockey League players have come down with mumps in the past two months, according to CBS Sports. The outbreak seems to have started with the Anaheim Ducks (four players), but it soon spread to other teams, including the Minnesota Wild (five players), the New York Rangers (one player), and the New Jersey Devils (two players). A dozen cases of mumps on teams with a total player count of only a couple hundred players is a lot, considering that there have been only about a thousand cases of mumps in the entire country this year, according to the CDC.

But it makes sense, actually. Mumps is spread by contact with infected saliva or mucus, usually via coughing or sneezing. The close-knit conditions in a hockey locker room and frequent intense physical contact on the ice would be ideal conditions for the disease to spread. An infected person can infect others for several days before they exhibit the typical symptoms, of tiredness, fever, headaches, muscle pain, and glandular swelling - plenty of time for a hockey player to inadvertently pass his infection on to a player from another team. The Anaheim Ducks played the Minnesota Wild in mid-October. In addition, some infected persons never show the typical symptoms at all. Yet they can still infect others, making it hard to trace and eradicate an outbreak.

Although the NHL isn't too worried (mumps is not a particularly life-threatening disease), the outbreak has been disruptive in that players have had to miss games while they are sick. The league is warning teams and players about the outbreak in a hope of stemming the disease's spread. Most of the players had already been vaccinated against mumps (mumps is primarily disease of childhood, and vaccination against mumps is part of the normal vaccination regimen for children), but health officials report that the vaccine is not 100% effective; it's more like 78%. An additional vaccination can boost effectiveness to 88%, and some teams are offering the second vaccination as a precaution.

Sunday, November 30, 2014

The Declining Availability of Fresh Water

The natural fresh water cycle (the cycling of water from oceans to the atmosphere, becoming precipitation in the form of rain and snow) is the source of the fresh water in the Earth's lakes, streams, and underground aquifers. The water cycle is timeless and largely unaffected by man, except for the probable influence of global warming. But the supply of clean fresh water available to humans (where humans choose to locate) is slowly but surely declining.

Many western U.S. cities rely primarily on water derived from the winter snowpack in nearby mountain ranges. The cities are growing and demand for water is up. To make matters worse, the winter snowpack has been declining in recent years. Some of the snowpack's decline may be due to global warming, but it may also be partly due to normal decades-long cyclic fluctuations in the water cycle. Centuries-old glaciers have been receding; some have disappeared entirely. If the current 30-year trend continues, Montana's Glacier National Park in may not have a single glacier by 2030. This does not bode well for Western lakes and streams.

Some human populations rely heavily on ancient underground aquifers for water to irrigate thirsty crops. China, India, and the U.S. plains States all rely heavily on aquifers that are not being replenished at the rates at which they are being used. Wells in some areas are going dry, leading to a loss of agricultural productivity.

Pollution of freshwater is a constant concern. Industries that use a lot of water or that run the risk of polluting rivers and streams, such as mining for coal, copper, and gold, face increasing government regulation or outright opposition from environmental groups. The world's largest gold mining company, Barrick Gold, shut down a major investment in a massive mine in Chile due in part to costs related to the risk of polluting nearby rivers and streams.

These are not problems that are going to go away quickly. Humans will have to adapt. We'll need to reduce water use in our homes, recycle water wherever possible, locate our human populations nearer to abundant supplies of fresh water, develop agricultural crops that require less water, irrigate crops more efficiently, and improve industrial techniques that require water. Some of these actions are already being taken. As they must, if we are to prosper in the long run.

Wednesday, November 26, 2014

The Benefits of Genetically Modified Crops

Opponents of genetically modified (GM) crops are quick to point out the potential risks involved in planting GM crops and in eating foods with GM ingredients. Some of the risks, such as the potential for encouraging the emergence of "superweeds" that are resistant to the herbicides used on GM crops, and the inadvertent cross-pollination of normal crops by GM crops in nearby fields, are real. Others, such as the potential for causing future unspecified human health problems, are as yet undocumented.

Are there any known benefits of GM crops, other than for the farmer? A recent meta-analysis published in PLOS one concludes that indeed there are. The authors of the analysis reviewed all of the previous reports of the economic and agricultural impacts of three GM crops (soybeans, maize, and cotton) published in English between 1995 and early 2014; 147 studies in all. They found that in addition to improving farmer's profits by 68%, the use of GM crops increased crop yields by 22% and decreased chemical pesticide use by 37%.

Increased profits for farmers is not a bad thing, for it means they pay more taxes and have more money to spend (stimulating the economy). Increased crop yields allows more people to be fed per acre of agricultural land; something to think about as Earth's human population continues to rise even as the amount of arable land remains constant. Finally, reducing chemical pesticide use by more than a third can only be good for the environment.

I'm not saying that GM crops are perfect. I'm well aware that there are risks, some of which may still be unknown. I'm just saying that in any dialogue about whether we should allow GM crops, we should consider both the risks and the benefits, and not just focus on one or the other. Do not be fooled into thinking that there is only one side (yours?) in this debate.

Saturday, November 8, 2014

Increasing Incidence of Colorectal Cancers in Young People

A review of the nearly 400,000 reported cases of cancers of the colon and rectum between 1975 and 2010 reveals some interesting trends. Overall, the incidence of colorectal cancers declined by just under 1% per year, due to a steady decline in persons 50 years of age or older. However, the incidence of colorectal cancers rose in the youngest age group; persons aged 20-34. Based on current trends, rates of colorectal cancers in this age group will nearly double by 2030.

The current study provides no information regarding the cause of the upward trend. But this is how science works; based on an observation, (a rising rate of colorectal cancers in young people) a hypothesis must be formed and further study undertaken to test it.

Perhaps by 2030 we'll know why colorectal cancers are increasing in young people, and also know what to do about it. The optimist in me hopes so.

Thursday, November 6, 2014

The FDA approves a Vaccine for a Rare Meningitis

Last fall an outbreak of a rare form of meningitis called serotype B occurred on the campus of Princeton University. Months later a similar outbreak occurred at the University of California Santa Barbara (UCSB). Although a vaccine against serotype B meningitis was available in Canada and Europe, it had not yet been approved in the U.S. Nevertheless, because of the dangerous nature of meningitis and the ease with which the disease might spread on college campuses (it's spread by close contact such as kissing or sharing eating utensils) the FDA granted emergency approval of the vaccine, just for students of Princeton and UCSB. The vaccine worked, the outbreaks subsided, and a greater crisis was averted.

Recognizing that the normal approval process for a vaccine or drug can take years, the FDA has developed a fast-track approval process for vaccines and drugs that meet certain criteria. Two competing vaccines against meningitis serotype B were fast-tracked under this program, and last week the FDA approved the first one, Pfizer's Trumenba.

And that's interesting, because the vaccine approved on an emergency basis for the students of Princeton and UCSB was the other vaccine, called Bexero, made by Novartis. We hope it's just that Pfizer just did a better (and faster) job of satisfying the FDA of its product's safety and effectiveness.

Now that a vaccine for meningitis serotype B is available, should it become part of the standard vaccination schedule for all children? That hasn't been decided yet, but the decision rests with the Centers for Disease Control and Prevention (CDC), not the FDA.