Case Study: To Give a Shot or Not
Elena and Daris are expecting their first child. They are excited for the baby to arrive, but they are nervous as well. Will the baby be healthy? Will they be good parents? In addition to these big concerns, it seems like there are a million decisions to be made. Will Elena breastfeed or will they use formula? Will they buy a crib or let the baby sleep in their bed?
Elena goes online to try to find some answers. She finds a website from an author who writes books on parenting. On this site, she reads an article that argues that children should not be given many of the standard childhood vaccines, including the measles, mumps, and rubella (MMR) vaccine.
The article claims that the MMR vaccine has been proven to cause autism and gives examples of three children who came down with autism-like symptoms shortly after their first MMR vaccination at one year of age. The author believes that the recent increase in the incidence of children diagnosed with autism spectrum disorders is due to the fact that the number of vaccinations given in childhood has increased.
Elena is concerned. She does not want to create lifelong challenges for their child. Besides, aren’t diseases like measles, mumps, and rubella basically eradicated by now? Why should they risk the health of their baby by injecting them with vaccines for diseases that are a thing of the past?
Once baby Juan is born, Elena brings them to the pediatrician’s office. Dr. Rodriguez says Juan needs some shots. Elena is reluctant and shares what she has read online. Dr. Rodriguez assures Elena that the study that originally claimed a link between the MMR vaccine and autism has been found to be fraudulent and that vaccines have repeatedly been demonstrated to be safe and effective in peer-reviewed studies.
Although Elena trusts their doctor, she is not fully convinced. What about the increase in the number of children with autism and the cases where symptoms of autism appeared after MMR vaccination? Elena has a tough decision to make, but a better understanding of science can help her. In this chapter, you will learn about what science is (and what it is not), how it works, and how it relates to human health.
Chapter Overview: The Nature and Process of Science
In the rest of the chapter, you'll learn much more about science, including how scientists think and how they advance scientific knowledge. Specifically, you'll learn that:
- Science is a distinctive way of gaining knowledge about the natural world that is based on evidence and logic. Scientists assume that nature can be understood with systematic study; that scientific ideas are open to revision, although sound scientific ideas can withstand repeated testing; and that science is limited in the types of questions it can answer.
- A scientific theory is at the pinnacle of explanations in science. A theory is a broad explanation for many phenomena that is widely accepted because it is supported by a great deal of evidence. An example of a theory in human biology is the germ theory of disease. It took more than two centuries of research to provide enough evidence that microorganisms ("germs") cause disease for this explanation to become widely accepted and attain the status of a theory.
- The process of science is epitomized by scientific investigation. This is a procedure for gathering evidence to test a hypothesis. A scientific investigation typically involves steps such as asking a question based on observations and formulating a hypothesis as a testable answer to the question. It also generally involves collecting data as evidence for or against the hypothesis, drawing conclusions, and communicating results. In reality, the process of science is not simple and straightforward. The process actually tends to be nonlinear, iterative, creative, and unpredictable. "Doing" science can be very exciting!
- Scientific experiments are a special type of scientific investigation, in which variables are manipulated by the researcher to test expected outcomes. Experiments are performed under controlled conditions to mitigate the effects of other variables on the outcome variable. Experiments provide the best evidence that one variable causes another variable in scientific research. An example of an experiment in human biology is the astounding public health experiment to test Salk's polio vaccine that was undertaken in 1953. Some 600,000 children received a vaccine injection; another 600,000 received a placebo injection of useless salt water. The vaccine group had a significant drop in polio cases relative to the placebo group, providing support for the hypothesis that the vaccine prevented the disease.
- Many questions in human biology are not amenable to experimental research. Consider the question: "Does smoking cause lung cancer?" It would not be ethical to deliberately experiment with human subjects by exposing them to harmful tobacco smoke in order to see whether they develop lung cancer. For questions like this, observational studies are done to look for correlations between variables. For example, Doll and Hill gathered information on past smoking habits from a large sample of lung cancer patients and another large sample of controls without lung cancer. Smoking and lung cancer were found to be correlated. Correlation does not imply causation, but it can be a big hint!
- Research involving human subjects presents special challenges to scientists. Until the 1970s, there were few ethical guidelines for researchers to follow when studying human subjects. A shamefully unethical syphilis study called the Tuskegee study changed all that. The Tuskegee study was conducted on African-American men in Alabama from 1932 to 1972. This study was done to see the progression of syphilis. In this study, the control group with the disease was not treated for syphilis. When details of the study were leaked to the media, the public was outraged and the U.S. Congress got involved. In 1974, Congress passed important legislation to protect human subjects in scientific research projects. Chief among the protections was the necessity of informed consent.
As you read this chapter, think about the following questions:
- What do you think about the quality of Elena’s online source of information about vaccines compared to Dr. Rodriguez’s sources?
- Do you think the arguments presented here that claim that the MMR vaccine causes autism are scientifically valid? Could there be alternative explanations for the observations?
- Why do you think diseases like measles, polio, and mumps are rare these days, and why are we still vaccinating for these diseases?