Step 1:
Vaccination of individuals
Aside from surviving a bout with a disease, Nature provides us with very few
certain methods of avoiding disease.
- Living a healthy lifestyle and providing our bodies with good
nutrition keeps us strong, but many people who do both of these are still susceptible and fall
ill with colds, flu, or other contagious diseases when outbreaks occur.
- A mother who breast-feeds shares some antibodies and other
protective substances, and therefore her immunity,
with her baby, but this protection is short-term. Mothers also pass antibodies to the fetus
before birth via the placenta.
- Some people are immune
to certain diseases from birth via their genetic lineage (the genes passed to them from their
ancestors); for example, some from the Mediterranean inherit a genetic trait that enhances
resistance to malaria. However, this kind of genetic advantage sometimes has a high biological
price tag. For a fraction of people with the malaria-resistance trait, for example, the price
is sickle cell anemia, a condition in which red blood cells take on a crescent shape and clog
tiny blood vessels, slowing or blocking circulation to the rest of the body and causing fever
and severe pain. About 1 in 10 American children of African heritage carry the trait for
sickle cell, and about 1 in 500 develop sickle cell disease.(20)
The remaining choice for an individual to avoid disease is to avoid
everyone and everything at all times. Even a dedicated hermit can't do this. So, we are very
fortunate to have another choice. We can live healthy, longer lives by being immunized. In 1996,
almost 82 million immunizations were
given safely to American infants, children, and adults.(21)
Step 2:
Establishing community immunity
Community
immunity is a vital second step in protecting against many diseases that are spread from
one person to another, such as diphtheria, measles, and mumps. The greater the proportion of
people who are immunized, the greater are the effects of community immunity. With community
immunity, people in whom an immunization has failed or worn off, and the people who cannot or have
not had the opportunity to be immunized, will still be protected. Community immunity is not
helpful in preventing a disease like tetanus, which is caught not from people but from injuries
such as cuts or punctures, allowing the microorganism
Clostridium tetani (which is found in soil) and its toxins to invade the body.
Step
3: Practical measures to prevent disease
Immunization is our very best defense against disease. Other
practical measures, such as quarantine,
sanitation, hygiene, proper food handling, and changes in lifestyle vary in their prevention
potential, depending on the disease. A vaccine against malaria would result in more
effective and sustained prevention, but none has been developed yet.
Quarantine means isolation of an individual with a highly
contagious disease from the rest of the community. Quarantine is a two-part responsibility. It
means that others should protect you by isolating themselves when they are ill, and that you
should protect others by isolating yourself when you are ill. Unfortunately, for many diseases,
transmission (spread) of organisms that cause the disease occurs very early in the course, often
before the illness has declared its presence clearly enough to stay home from work or school.
Meanwhile, the infected individual may have already spread the disease to many others. Another
problem with quarantine is that our society is not always supportive of staying home from work or
school when we are not feeling well. So, while we recognize self-quarantine as a helpful and
responsible thing to do, it is not a reliable way to prevent the spread of disease.
Eliminating sources of contamination, such as unsafe water
supplies or improperly handled meat, spares much human suffering from certain types of diseases,
but would have little or no impact on diseases like measles, pertussis, polio, or mumps. In
countries where the rate of malaria is high, control or elimination of the mosquitoes that
transmit the disease is an important measure. However, a vaccine against malaria would result in
more effective and sustained prevention (none has been developed yet).
A change in lifestyle can be a small but significant change.
For instance, washing hands more frequently will prevent hand-to-mouth transfer of some
disease-causing agents.
 |
Footnotes |
20. Campbell NA. Biology. Menlo Park,
CA: Benjamin/Cummings Publishing, 1987:275.
21. National Immunization Program,
Centers for Disease Control and Prevention. Vaccine doses distributed in the United States by
funding source: calendar year 1996.
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