Archive for November, 2013
Actually, the heading of this post is a little misleading because I got my flu shot about two weeks ago, but it makes a catchy title. But it does reflect a subject I’d like to talk about because of recent events, especially posts on Facebook and articles in the news. Vaccines have come under fire the last ten years (perhaps more than that) or so for several reasons, but mainly because of side effects, real or perceived. Some people refuse to take a vaccine because they don’t want “that stuff” in their body. This represents a shift in thinking by the public over the last twenty to thirty years. Back then, vaccines were seen as a way to help prevent disease, and public acceptance was high. Now it isn’t. For many reasons.
Vaccines have done a lot for humanity (not to mention dogs and cats and other animals). Smallpox was eradicated from the earth by a vaccine. Polio was on it’s way out until it appeared in Syria in the midst of the civil war there, but the outbreak is being treated with vaccines. The real problem with polio is that if the war prevents children from being immunized, the disease could spread, leading to serious illness in children, especially in refugee camps. Polio is spread by contaminated water and there’s a lot of that in war zones and refugee camps. Other diseases, especially childhood maladies such as measles, mumps, chickenpox, diphtheria, and whooping cough, as well as diseases that affect older people as well as children such as meningitis, pneumonia, and shingles, are being attacked with vaccines. The overwhelming evidence is that the vaccines work. And work well. Some diseases such as measles and whooping cough (also known as pertussis) have made comebacks in the last few years because children aren’t getting their vaccines. Parents don’t want them for their kids. Too many side reactions, they say, such as autism. But the link between autism and vaccines was destroyed several years ago, and there isn’t any good scientific evidence for such a link.
Many of the comments I’ve heard about vaccines, and this applies especially to flu vaccines, is that they don’t work, or at least don’t work very well. Their efficacy is only about 60 percent, and opponents of vaccines jump on that statistic as a reason why they don’t want to get a flu shot. They point out other things too, such as the incidence of side reactions and bad diseases that strike down flu vaccine recipients. Especially Guillen-Barre Syndrome. (GBS is called an ascending paralysis because it starts in the feet and legs and works its way up. It can affect breathing and a patient may have to be put in a drug-induced coma and put on a respirator for a while, but it usually goes away spontaneously.) But these side effects are extremely rare and shouldn’t lead anyone to not get a flu shot. I haven’t heard of much GBS after flu shots since the flu vaccine disaster in 1976.
The most important reason to get a flu shot is the protection it affords. A vaccine that is 60 percent effective will protect 6 out of 10 people who get the shot. (A person is “immune” if antibodies to the virus appear in his bloodstream.) Now if that looks bad, consider that in a large population, if 60 percent of the people are protected, the number of susceptible people is reduced to 40 percent of what it was. A virus such as influenza has to have a large group of susceptible individuals in order to cause an epidemic, that is, spread from one person to another. If 60 percent of the population is immune, the virus will find it much harder to spread. That means that, in a sense, the presence of immune people helps protect the 40 percent who are not immune because they’re less likely to be infected. They’re less likely to come in contact with an infected person. Sure, we’d like a vaccine to be 99 percent effective, but if it only protects 60 percent, we’ll take it anyway.
Another reason people refuse to get flu shots is because the particular strain of influenza virus that is currently circulating is not in the vaccine. Sometimes this does happen because vaccine manufacturers have to guess which strains to put in the vaccine months in advance. I don’t worry too much about that because many strains of influenza are related and immunity to one is partially active against another. Not always, especially if a new strain comes through, but on a yearly basis, the cross-reactions are there. I’ve been getting flu shots for years now, and each year the shot, even if it has different strains in it, will boost my immunity and help protect me against most strains currently circulating. That’s another reason for getting a yearly shot, it boosts immunity over the years.
I’ve heard the argument that flu vaccines have so much other stuff in them that people don’t want to get a shot because of the nasty chemicals. One chemical that used to be in vaccines is mercury, but that was in the form of merthiolate, which is a preservative, and that’s been eliminated from many vaccines. The other “chemicals” said to be in vaccines I can’t comment on, but I haven’t had any trouble. They’re probably in very low concentrations, if they’re there at all.
In short, I strongly urge everyone to get a flu shot, as well as other vaccines. Vaccines work, that is established, and the more people who get a shot, the better they will work, regardless of their “limited” efficacy.
This blog post is limited in scope, admittedly, because I have limited room to work. I normally post five to six hundred words, and this one is already over 1000. If you want to know more about vaccines, Google it and see what you get. You’ll get a lot of negative stuff, but you’ll also get some positive comments. Make up your own mind. Then go get a flu shot. It helps the rest of us.
Last week in my regular blog I wrote that we shouldn’t expect astronomers to find an Earth-sized planet out there very soon. I may have spoken too soon. After that post, two articles appeared on Yahoo News about that very subject. One story, from Space.com, reported that the NASA Kepler astronomical satellite telescope had found in the last year over 800 new planets orbiting stars outside out solar system, and 104 of them could be potentially habitable. Only ten of them, though, are the size of Earth. But keep in mind that we are still in the early stages of examining these planets, and just because they are Earth-sized doesn’t mean they have life on them. Many other factors will determine the presence of life, and it will be a while before a complete determination is made just which ones are potential life-possessing planets. It will take time.
The second article, from the Associated Press, reported that there may be as many as 8.8 billion Earth-sized, just right planets in our galaxy. That takes into account only planets that orbit stars like our sun, exist in the habitable zone where life as we know it could develop, and are about the size of Earth. Out of all the planets in the Milky Way Galaxy, those conditions narrow the field quite a bit, but still take into account, by their estimation, several billion planets. At first I thought that number sounded high, but I realized almost immediately it wasn’t. Consider the Kepler spacecraft I mentioned above. It has found thousands of planets, yet it examines only a tiny portion of the sky. By expanding that potential over the whole sky and throughout the entire galaxy, the number of planets, and even the number of potential life-possessing planets, becomes staggering. That’s where they got the number 8.8 billion. That’s an 88 followed by eight zeros. Now, even though the conditions for life existing on a planet’s surface are extremely narrow and stringent and will eliminate most of those 8.8 billion, the chances should still be relatively high that somewhere within those remaining planets life has evolved. Taking it out to the point of intelligent life would reduce that number even further, but it’s still possible. And taking it out to intelligent life capable of spaceflight would reduce the numbers even further. In fact, I suspect that the number of planets having intelligent life capable of spaceflight might be as low as 80, or even 8, not counting our own. Some of those worlds where spaceflight is possible may be on the other side of the galaxy where we can’t see them. In any event, finding life of any sort will be a challenge, and as I said last week, it will take time. Get used to it.
A few days ago I read an online article about how astronomers had discovered a new planet outside our solar system that seemed to be similar in size and density to Earth. The natural inclination of humans upon discovering a planet roughly the same size as our own is to ask, does it have life on it? Well, in this case, no. It seems that the newly discovered planet orbits so close to its sun it must be molten on the surface. Several thousand degrees (around 5000 F) on the surface. Nothing we know as life is going to develop in that environment.
I’ve always found it interesting that the search for extra-solar planets (and we’ve found over a thousand so far) is always mixed up with the question of life on these planets. Does it have life? we ask, over and over . We don’t look for planets just to see what’s out there, we have to ask about the conditions for life. So far no planet discovered has even come close to having the proper mixture of water, temperature, carbon compounds, oxygen in an atmosphere, and other chemicals such as nitrogen, phosphorus, sulfur, sodium, chloride and so forth to provide the proper incubator for life to develop. (Of course, that’s life as we know it. Other forms of life could exist in wildly other environments.) With all these planets that have so many disadvantages and drawbacks preventing life from developing on their surface, it’s a wonder that we keep asking the question. The large number of known extra-solar planets and the fact that none are even remotely close to having life is telling us something. Telling us not so much to quit asking the question (we’ll never do that) but that the number of planets that actually do have life is going to be small. Very small. In our own solar system, only one moon of one planet (Europa, a moon of Jupiter) is likely to have life outside Earth. Even Mars likely never had living organisms on its surface.
Planets form from the accumulation of the interstellar dust that didn’t get incorporated into a newly born star, and life is not by any means a requirement of planetary existence. Planets take all sorts of different sizes and (perhaps) shapes. They have markedly different temperatures and surface characteristics. Life requires an extremely narrow range of ingredients and we haven’t found it yet anywhere outside Earth. It may be a while before we do, if ever. We’re in for a long search. Get used to it.