Why Vaccinate?
Protecting Against Serious Diseases
In essence, vaccines have been meticulously developed and formulated to combat and mitigate the significant health risks associated with various diseases. To illustrate the importance of vaccination, let's delve into specific details regarding these vaccine-preventable illnesses.
Diphtheria, Tetanus, and Pertussis (DTaP): Diphtheria, characterized by the formation of a membranous coat in the tonsillar and pharynx region, can initially resemble a common upper respiratory infection with fever. However, in severe cases, it can lead to airway obstruction, paralysis, cardiac complications, and even death, with a mortality rate of 5-10%. Although the United States has seen a substantial decline in actual cases, global outbreaks persist, particularly in the former Soviet Union.
Tetanus, often associated with injuries like stepping on a rusty nail, can manifest in three forms: generalized, localized, and cephalic. Generalized tetanus involves severe muscular spasms and jaw locking, resulting in a 10% mortality rate. The neurotoxin produced by Clostridium tetani is responsible for the disease. The highly contagious pertussis, or whooping cough, may initially mimic a common cold but can lead to apnea, seizures, and death in infants. Data from the 1990s show a 1% case mortality rate for children under 2 months and less than 0.5% for infants between 2 months and 1 year. Adults, even if fully immunized as children, have experienced resurgence in pertussis cases due to waning immunity, posing a risk to infants not yet fully immunized. The "a" in DTaP signifies "acellular" and was introduced due to concerns about adverse reactions to the original DTP vaccine.
Polio: Polio was widespread before the introduction of the first vaccine over 50 years ago. Although many infected individuals remain asymptomatic, about 1% develop paralysis, which can lead to permanent disability and sometimes death. Two types of polio vaccines exist: oral and inactivated forms. The oral vaccine, an attenuated virus, is used in many parts of the world, whereas the inactivated form, injected, is primarily used in the United States.
Haemophilus Influenzae b (Hib): Infections caused by Hib encompass meningitis, pneumonia, and epiglottitis, an extremely severe throat condition. The Hib vaccine has been incredibly effective in preventing these infections, reducing invasive diseases by 99%.
Hepatitis B: This liver-damaging disease can lead to lifelong infection, cirrhosis, liver cancer, liver failure, and death. In infants, the primary concern is perinatal transmission during delivery, rather than in utero. Hence, pregnant women are tested for Hepatitis B status during pregnancy.
Pneumococcal Infections: The 13-serotype pneumococcal vaccine has successfully prevented various childhood illnesses, from ear and sinus infections to severe pneumonias and meningitis. Since its introduction in 2000, all invasive diseases caused by this bacterium have decreased by 80% in children under 2 years of age.
Rotavirus: Rotavirus, the leading cause of gastroenteritis or "stomach bugs" in children worldwide, is now preventable through oral vaccines. In the few years since their introduction, the U.S. has seen a significant reduction in cases, emergency room visits, and hospitalizations. Importantly, there has been no increased incidence of intussusception, a prior vaccine concern involving the telescoping of one part of the small intestine into another.
Varicella (Chickenpox): Chickenpox, marked by itchy skin lesions, fever, and overall discomfort, was highly contagious, often spreading by mere proximity. Complications included hospitalization, encephalitis, and death in children. Newborns were also at risk if their mothers contracted chickenpox shortly before or after giving birth. Since the introduction of the vaccine in the mid-1990s, these concerns have significantly diminished.
Hepatitis A: Although typically a self-limited illness with symptoms like poor appetite, jaundice, fever, and general malaise, it can affect up to 30% of children under 6 years of age. Severe acute liver failure is rare, with a case-fatality rate of about 0.5%, and it does not lead to chronic liver disease. Transmission occurs primarily through the fecal-oral route, with an incubation period of approximately 28 days.
Measles, Mumps, and Rubella (MMR): Measles presents with fever, rash, cough, runny nose, and specific mouth lesions known as Koplik spots. Complications include encephalitis, subacute sclerosing panencephalitis (SSPE), and death. Mumps results in salivary gland swelling, particularly in the parotid glands, leading to hearing deficits, neurological issues, and orchitis. Rubella symptoms are usually mild, including rash, swollen lymph nodes, and low-grade fever. The main concern with rubella is when pregnant women contract the virus, potentially causing miscarriage, fetal death, or congenital rubella syndrome with various birth defects.
Meningococcal Disease: Meningococcal disease is associated with severe bloodstream infections, meningitis, or a combination of both. It can lead to limb loss, neurological deficits, or death, with rapid disease progression often occurring. Dormitories, military barracks, and summer camps present environments conducive to the rapid spread of the disease among non-immunized individuals. Those with spleen disorders or specific immune system conditions are particularly vulnerable.
Human Papillomavirus (HPV): HPV includes numerous virus types, with types 16 and 18 responsible for approximately 70% of cervical cancer cases. Types 6 and 11 are linked to 90% of genital warts cases. Transmission occurs through genital sexual contact, with many infected individuals unaware of their status. Newborns can also contract genital HPV during delivery, leading to throat warts. In the United States, about 20 million people are currently infected with HPV. HPV vaccines, available in two- or three-dose schedules, protect against specific types of HPV. The vaccine is a remarkable advancement in preventing cancer, with no evidence of an increased Guillain-Barré syndrome incidence, even after millions of doses administered.
