News :Immunizations: First Line of Defense Against Infectious Diseases

Posted on Monday, September 29, 2008

The start of school means new shoes, No. 2 pencils, a new box of crayons – and shots. While immunizations may not rate high on a child’s list of back-to-school activities, they are his or her best line of defense against the serious infectious diseases like measles and polio that used to affect children by the thousands. Today in the U.S., most school districts mandate that children receive immunizations against childhood diseases before enrollment, but a majority of U.S. adults still fail to obtain vaccinations that could protect their health from potentially deadly diseases.

A national survey performed last year by the U.S. Centers for Disease Control and Prevention (CDC) showed that less than 70 percent of older Americans had received flu and pneumonia shots. Only 2 percent of eligible Americans had received a whooping cough booster shot, and only 10 percent of eligible women and girls had received the HPV (Human Papillomavirus) vaccine. Many Americans didn’t even know these vaccines were available.

Most medical experts agree that the benefits of vaccines outweigh the risks. While there are some risks, most adverse reactions are mild, such as soreness or swelling at the injection site. Severe allergic reactions are extremely rare; generally less than 1 in a million doses, and present a much lower risk to health than the diseases they prevent.

Vaccines provide immunity to disease by causing the body to produce proteins, called antibodies, to a specific disease. These antibodies neutralize toxins and destroy disease-carrying organisms, providing protection against the specific disease. Once the body develops antibodies to a disease, future contact with the disease organism causes the immune system to immediately produce antibodies to fight it, thus protecting the individual from subsequent attack. A vaccine may provide either active or passive immunity:

• Active immunity occurs when the body produces antibodies in response to exposure to the disease organism. Exposure can occur by infection through contraction of the actual disease or by vaccination with a killed or weakened form of the organism. Active immunity generally takes several weeks to develop but is long-lasting and often, as in the case of vaccinations against many childhood diseases, lifelong.

• Passive immunity occurs when antibodies to a disease are given to an individual as opposed to being produced by his or her immune system. For example, the immunity a newborn receives from the mother’s placenta. Antibody-carrying blood products such as immune globulin are sometimes used to provide passive immunity when immediate protection is required. While passive immunity lasts only a few weeks or months, its protection is immediate.

The CDC website provides a comprehensive list of common vaccines for children and adults, their possible complications, and recommended vaccination schedules. Additionally, with flu season just around the corner, the CDC recommends that you receive a flu shot if you meet one or more of the following criteria:

• All persons who want to reduce the risk of becoming ill with influenza or of transmitting influenza to others
• All children aged 6 months to 18 years old
• All persons aged 50 years and older
• Children and adolescents (aged 6 months to18 years) receiving long-term aspirin therapy
• Women who will be pregnant during the influenza season
• Adults and children who have chronic pulmonary (including asthma), cardiovascular (except hypertension), renal, hepatic, hematological or metabolic disorders (including diabetes mellitus)
• Adults and children who are immunosuppressed
• Residents of nursing homes and other chronic-care facilities
• Health-care personnel
• Healthy household contacts (including children) and caregivers of children aged less than 5 years and adults aged 50 years and older
• Healthy household contacts (including children) and caregivers of persons with medical conditions that put them at higher risk for severe complications from influenza

Some medical experts are concerned that the failure of last year’s flu shot to correctly target the most prolific strains of influenza and the resulting upsurge in flu cases last winter could discourage people from getting a flu shot this year. But as CDC influenza epidemiologist Joseph Bresee points out, last year was somewhat of an anomaly.

“Most years, the prediction is very good,” said Bresee. “In 16 of the last 19 years, we have had a well-matched vaccine.”

Because of the rapid mutation of the influenza virus, a new vaccine must be formulated each year based on researchers’ best estimates of the influenza strains that may become most prolific. Flu vaccines contain elements of the three families of flu virus: influenza A, types H1N1 and H3N2, and influenza B. In the average year, the vaccine has one or two strains updated.  In response to last year’s strain mismatch, the 2008 vaccine received a complete overhaul with all three strains being new to this year’s vaccine.

Periodically throughout history, influenza viruses cause global epidemics called pandemics. The great influenza pandemic of 1918-19 is estimated to have killed 675,000 Americans and between 30 and 50 million people worldwide, putting pressure on scientists to find a cure. The influenza A virus, which causes most endemic and pandemic influenza, was isolated in 1933, followed by isolation of the influenza B virus in 1940. By 1944 the first influenza vaccine was introduced in the U.S. Influenza pandemics in 1957-58 and 1968-69 killed 70,000 and 33,000 Americans, respectively, far fewer than in 1918-19.

Consider this: on average, every year influenza:

- Infects 60 million people
- Kills almost as many Americans as breast cancer
- Kills two to three times more Americans than HIV/AIDS
- Kills the equivalent to a major league stadium full of people

Annual flu vaccines are our greatest tool for avoiding another pandemic. Influenza poses the greatest risk to the very young and the elderly. Every year, Maxim Health Systems hosts thousands of on-site public flu shot clinics across the country to provide preventive care for a wide range of individuals. Flu shot clinics begin October 1 and continue through the end of the flu season.

Visit Maxim Health Systems’ website, http://www.findaflushot.com, and use our online Flu Shot Locator to find a flu clinic near you. Protect yourself and those you love. 

You can also apply to become a nurse at one of Maxim’s flu clinics by visiting www.maximnurses.com/apply.