Because the CDC’s Advisory Committee on Immunization Practices (ACIP) regularly meets to review and decide on vaccine policy, and because new vaccines are always in development while others are constantly being monitored for safety, the information in this appendix is likely to change. The most up-to-date information can usually be found on the CDC website, the CDC’s Pink Book, or in the CDC’s Morbidity and Mortality Weekly Reports.
General Info: Poliomyelitis (polio) is a viral disease that causes fever, sore-throat, flu-like symptoms, and pain in the limbs. In less than 1% of cases, the disease can progress to muscle weakness and paralysis that may be permanent. Paralysis of the respiratory muscles may also occur, which can lead to death. The last case of paralytic polio in the US occurred in 1999.
Two vaccines can prevent polio: an injectable inactivated vaccine (Salk) and a live-attenuated oral vaccine (Sabin). The U.S. has exclusively used the inactivated Salk vaccine since 1999. The oral Sabin vaccine is used in many developing countries, especially those where polio still occurs, because it provides better herd immunity. Before polio can be eradicated, all countries will need to switch to using only the inactivated vaccine.
In the US, children receive four doses of inactivated polio vaccine, at 2 months, 4 months, 6-18 months, and 4-6 years.
Effectiveness: 99% after 3 doses
Duration of Protection: The complete series provides lifetime protection.
Vaccine Complications and Risks: The live vaccine – no longer given in the U.S. – carries the risk of infecting 1 in every 1 to 2 million vaccine recipients with the poliovirus. The inactivated vaccine given in the U.S. only causes soreness where the shot is given.
Disease Complications and Risks: Even those who survive paralytic polio risk developing post-polio syndrome as older adults, about 30-40 years after they had the disease. The symptoms include muscle and joint weakness and pain, a wasting away of the muscles, fatigue, breathing or swallowing problems
Additional Considerations: While polio is no longer endemic in the US, it can be introduced by a person visiting from a country where it has not been eradicated: Pakistan, Afghanistan, and Nigeria. The case of Syria reveals how civil unrest or other circumstances can allow a disease to return since polio had been gone from Syria until the unrest from a civil war allowed it to return.
General Info: Chickenpox is a viral disease caused by a herpes virus called varicella zoster. An itchy rash usually starts on the head and then moves down the torso, arms, and legs. The pus-filled red bumps break open and crust over. Healthy children may have 200-500 of these pustules, which can also occur on the mucous membranes of the nose, throat, eyes, and vagina. Before the vaccine, approximately 4 million cases a year occurred, causing 11,000 hospitalizations and 100 deaths. After the vaccine, hospitalizations and deaths declined by more than 90%.
The varicella vaccine for children is a live weakened vaccine, available in the U.S. since 1995. Children receive two doses, at 12-15 months and at 4-6 years.
Effectiveness: Two doses are 88-98% effective against all varicella.
Duration of Protection: Because the vaccine was licensed in 1995, data is only available for 19 years, but the vaccine appears long-lasting since studies don’t show significant waning.
Vaccine Complications and Risks: Soreness and swelling at the injection site; fever in 1 of 10 doses; mild rash in 1 of 25; mild breakthrough disease occurs very rarely with less than 50 (usually not itchy) lesions and often no fever; in extremely rare cases, someone with breakthrough disease can infect another household member if immunocompromised. Fever-caused seizures or pneumonia are extremely rare.
Disease Complications and Risks: Secondary bacterial infections of the lesions can occur, possibly leading to pneumonia, hospitalization, or death. Immunocompromised children, such as those with leukemia or HIV, may develop severe complications. Rare complications include meningitis, Guillain-Barre syndrome, etc. Adult infections are often more severe, especially among pregnant women, which results in death of the fetus or newborn in more than 30% of cases.
Like other herpes viruses, varicella can stay dormant in the body for life and can cause shingles (herpes zoster), a recurrent infection for which there is an adult vaccine.
Additional Considerations: The chickenpox vaccine also reduces the risk of shingles. Researchers initially had concerns that the introduction of the chickenpox vaccine had contributed to an increase in shingles cases in the general population, but the most recent research has shown this not to be the case. This disease is also the vaccine-preventable illness most commonly implicated in intentional infections through “pox parties.” While it is true that the death rate for chickenpox is very low, it is not zero, and a new threat today that did not exist in past decades is MRSA, methicillin-resistant staphylococcus aureus. Each open sore in a chickenpox infection is an opportunity for this hard-to-control antibiotic-resistant bacterial infection to enter.
General Info: Rotavirus is a viral gastrointestinal illness that causes severe diarrhea. Before the vaccine, It was the most common cause of severe gastroenteritis in infants and children in the U.S., with 3 million cases, more than 400,000 physician visits, 200,000 ER visits, 55,000-70,000 hospitalizations, and 20-60 deaths each year. It still causes more than half a million deaths annually worldwide.
The current rotavirus vaccines, RotaTeq (2006) and Rotarix (2008) are live weakened vaccines given orally. Rotarix requires two doses ( 2 and 4 months), and RotaTeq requires three doses (2, 4, and 6 months).
Effectiveness: 74-87% against any rotavirus gastroenteritis; 85-98% against severe gastroenteritis
Duration of Protection: We only have data from 2006, but we know the vaccine protects children at least through early childhood, when their risk is greatest.
Vaccine Complications and Risks: Mild temporary diarrhea or vomiting, irritability, or fever. The most serious possible complication relates to intussusception, a bowel blockage that may require treatment in a hospital and/or surgery. Risk in the first week after the vaccine ranges from in 1 of 20,000 (Rotarix) to 1 of 100,000 (RotaTeq).
Disease Complications and Risks
Severe diarrhea, dehydration
Additional Considerations: All doses must be given before a baby turns 8 months old. It’s best to stick to RotaTeq or Rotarix, not to mix and match. Breastfeeding has not been shown to limit effectiveness.
Rotavirus is still circulating in the U.S., and the risk of getting rotavirus without being vaccinated is higher than the risk of intussusception with the vaccine (in raw numbers). Intussusception has clear clinical symptoms and, as long as it is identified in a timely way, can be treated in one of three ways with good outcomes. First-line treatment does not require surgery, but if that fails, surgery is usually necessary. There is no treatment for rotavirus except fluids and support until the disease runs its course. Both rotavirus and intussusception often require hospitalization, and both can cause death if not treated or if complications develop, but death from either is extremely rare in the U.S.
General Info: There are various flu vaccine types each year, usually quadrivalent (four-strain) ones. The injections are inactivated vaccines, and the nasal vaccine is a live weakened vaccine, not recommended for older adults, pregnant women, children under age 2, or immunocompromised individuals. In the U.S., children aged 6 months and older are recommended to receive influenza immunization each year, starting with two doses during their first flu season.
Effectiveness: Varies greatly, depending on how well public health officials predicted the strains that would circulate during flu season and depending on whether any new strains appear. It’s ranged from approximately 20% some years to a rare 70% other years. It typically averages about 50-60% effective
Duration of Protection: Immunity from seasonal vaccine wears off, especially in those with compromised immune systems, so it’s necessary to get a new shot each season.
Vaccine Complications and Risks: The vaccine absolutely cannot give you the flu. It can, however, cause soreness, redness, or swelling where the shot was given; hoarseness; sore, red, or itchy eyes; cough, fever, aches, headache, itching, or fatigue. An estimated 1 in 1 million doses could involve a severe allergic reaction. No confirmed deaths have been shown to be caused by the flu vaccine. Individuals with egg allergies can get the vaccine but should consult an allergist.
Disease Complications and Risks: Pneumonia is the most common severe complication. Each year hospitalizations are in the tens or hundreds of thousands. Pregnant women are at higher risk for miscarriage or stillbirth. Deaths each year vary greatly, from 3,000 to more than 40,000.
Additional Considerations: Misconceptions abound about the flu vaccine, but the vaccine reduces the severity of illness even if the strains don’t match. The multi-dose vaccine contains the preservative thimerosal, which does not cause harmful effects. The 1976 swine flu vaccine was linked to an increase in cases of the nerve disorder Guillain-Barre syndrome, which a flu infection can also cause. Those with a history of Guillain-Barre should discuss the flu shot with their doctor. When given with the pneumococcal vaccine in children, there is an increased risk of a fever-caused seizure.
General Info: Haemophilus influenzae type B (not related to the influenza (flu) virus) causes a serious bacterial disease, most commonly in children under 5. Until the vaccine, 20,000 life-threatening Hib infections occurred in the U.S. each year, and 3-6% of those resulted in death.
Several different vaccine formulations are available, and either 3 or 4 doses are recommended (2, 4, (6), and 12-15 months). It can be given as part of combination vaccine with DTaP-IPV-Hib (Pentacel, 2008) or HepB-Hib (Comvax, 1996).
Effectiveness: Ranges from 95%-99% effective
Duration of Protection: It lasts at least until age 5, over the period when risk is greatest.
Vaccine Complications and Risks: Redness, swelling, or pain at injection site; fever occurs rarely.
Disease Complications and Risks: Hib infections can cause ear infections, bronchitis, bloodstream infections, pneumonia, infections of the trachea, joints, lungs, bones, or heart, as well as meningitis, an inflammation of the brain and spinal cord that can be fatal.
Additional Considerations: none
DTaP: Diphtheria, tetanus, acellular pertussis
General Info: Diphtheria is a bacterial infection that causes a thick membrane to cover the back of the throat. It can obstruct breathing, cause paralysis, heart failure, and even death in 5-10% of cases. However, since the introduction of the vaccine, almost no diphtheria cases occur in the U.S. at all.
Tetanus is a bacterial infection, also known as “lockjaw,” that causes painful muscle spasms throughout the entire body. Tetanus is not caught from other individuals. Instead, the bacteria lives on surfaces (such as rusty nails) that infect someone if introduced into the bloodstream.
Pertussis, also called whooping cough, causes severe coughing spells with the characteristic “whooping” that make it difficult for infants to eat, sleep, swallow, and breathe. It typically lasts several weeks but can last for months and can lead to pneumonia, seizures, brain damage, or death.
The complete DTaP vaccine series includes four doses, at 2, 4, 6, and 15-18 months, followed by boosters at 4-6 years and 11-12 years.
Effectiveness: Diphtheria: at least 97% efficacy in clinical trials
Tetanus: initially approximately 100%
Pertussis: initially 80-85%
Duration of Protection: Immunity from both tetanus and pertussis wanes over time, requiring boosters at 4-6 years and 11-12 years old. Adults should continue to get tetanus-containing boosters every ten years throughout adulthood with at least one booster containing pertussis (Tdap). Pregnant women should receive a Tdap booster in every pregnancy. The CDC is currently evaluating these recommendations as we learn more about how long immunity lasts, so the recommendations may change.
Vaccine Complications and Risks: Mild effects include fever, redness, swelling, soreness at injection site, fussiness, tiredness, and vomiting. Moderate ones include febrile seizure in 1 out of 14,000 children, crying for 3+ hours in 1 out of 1,000, or high fever over 105º F in 1 out of 16,000. The only severe risk is a serious allergic reaction in 1 of 1 million doses.
Disease Complications and Risks: Diphtheria can lead to myocarditis, neuritis, ear infections, and inability to breathe that results in death. Tetanus causes death in one in five cases. Infants under 3 months old are at the highest risk for death from pertussis.
Additional Considerations: Pertussis is highly infectious, second only to measles in terms of human diseases still regularly circulating in the world. It’s airborne, and one person can infect 12 to 17 other people while contagious, making herd immunity especially important for infants under 3 months old. Pertussis is still circulating (endemic) in the U.S. and peaks in cycles every five years or so. Cases began climbing again several years after the new vaccine was introduced because immunity from the current vaccine wanes, especially after five years. It is still very effective in the first few years, however. Researchers are continuing to work on an even more effective vaccine, perhaps available for newborns, that offers longer lasting immunity.
General Info: The hepatitis B virus causes a liver infection that can lead to short-term (acute) or long-term (chronic) diseases. Although primarily transmitted through blood and other bodily fluids (including sexual contact and saliva), the hepatitis B virus can live on surfaces for up to 7 days. The virus can also pass from mother to child during delivery, but this can be prevented with the birth dose. There is no cure for hepatitis B.
Infants should receive at least 3 doses of hepatitis B vaccine shortly after birth, at 1-2 months of age, and at 6-18 months of age. Hepatitis B is part of some combination vaccines, so sometimes four doses are given.
Effectiveness: Ranges from 80%-100% (usually around 95%)
Duration of Protection: Lifelong with no boosters needed.
Vaccine Complications and Risks: Soreness at injection site; fever or headache are rare, and allergic reactions (1 in 1 million) are extremely rare.
Disease Complications and Risks: Acute disease causes loss of appetite, tiredness, muscle and joint pain, diarrhea, vomiting, fever, headache, and jaundice. Approximately 5% of people (including up to 1.4 million Americans) develop chronic disease and can pass on the virus without even knowing they are sick. Chronic hepatitis B can lead to cirrhosis, liver cancer, and death. Approximately 3,000-4,000 deaths from cirrhosis and 1,000-1,500 deaths from liver cancer occur in the U.S. each year.
Additional Considerations: This was the first vaccine made that can actually prevent a type of cancer, which is more likely in those with hepatitis B in infancy. Until the vaccine, approximately 8,700 non-Asian children and 7,300 Asian-American children were infected with hepatitis B before age 10. More than 90% of babies who get hepatitis B at birth and about a third to a half of children aged 1 to 5 who become infected will all become chronic carriers. Transmission from the mother is the most common route, but even mothers tested for hepatitis B may have it if the test gives a false negative or the mother contracts it between testing and birth. Further, children can get hepatitis B in other ways, such as bites or scratches from peers in daycare and finding infected objects (needles, candy pieces, etc.) on the ground, since the virus can live in dried blood and on surfaces for a week.
General Info: The serious liver infection resulting from the hepatitis A virus causes fever, tiredness, loss of appetite, nausea, dark urine, jaundice, severe stomach pain, and diarrhea. The virus is spread by close personal contact or eating food or drinking water with the virus. Not everyone will experience symptoms, but up to 20% of people are hospitalized.
Two inactivated whole virus vaccines have been available for hepatitis A in the U.S. since 1995 and 1996. Children should receive two doses between 12 and 24 months old with at least 6 months between doses.
Duration of Protection: 20 years or longer (based on data since 1995)
Vaccine Complications and Risks: Soreness at the injection site, headache, loss of appetite, tiredness, or a very rare serious allergic reaction. No other serious adverse events have been reported.
Disease Complications and Risks: The death rate from hepatitis A is low, about 3 to 6 people per 1,000. However, the symptoms can be serious and cause adults to lose at least a month of work.
Additional Considerations: Because hepatitis A is a food-borne illness, it does not require another person to pass it along. For example, in 2013, a hepatitis A outbreak that sickened 165 people was traced to a frozen berry mix sold at Costco called Townsend Farms Organic Antioxidant Blend.
Pneumococcal conjugate vaccine (PCV)
General Info: The pneumococcal conjugate vaccine (PCV13) protects against infections caused by the bacteria Streptococcus pneumoniae, which is spread through respiratory droplets. These bacteria can cause ear infections, pneumonia, blood infections, and meningitis. An estimated 5 million cases ear infections occur each year in children under five.
The first pneumococcal conjugate vaccine (PCV7) was licensed in 2000 but was replaced by PCV13 to protect against additional serotypes of the bacteria. PCV13 is given to infants at 2, 4, 6 and 12-15 months of age.
Effectiveness: At least 90% effective against invasive disease
Duration of Protection: 4-5 years
Vaccine Complications and Risks: Redness and tenderness at the injection site, mild fever, fussiness, or drowsiness; severe allergic reactions are very rare.
Disease Complications and Risks: As many as 175,000 people are hospitalized each year with pneumococcal pneumonia, and more than half a million blood infections occur each year. Among these, 20-60% of patients die. S. pneumoniae is the leading cause of bacterial meningitis among children under 5 years in the U.S., and this inflammation of the membranes around the brain can cause deafness, brain damage, and death. Of the 3,000-6,000 cases of pneumococcal meningitis that occur each year, about 30-80% may die.
Additional Considerations: The introduction of this vaccine came with an added bonus: immunizing children reduced how much of the disease circulated in the community and therefore reduced disease in adults and the elderly, who are at some of the highest risks for complications from pneumonia.
The PPSV23 protects against more strains and has been available since 1983 but is primarily recommended for the elderly. The vaccine type doesn’t work well in children, though children over 2 with chronic illness or who are immunocompromised may receive it.
MMR (measles, mumps, rubella)
General Info: Measles is a viral disease causing a rash, cough, runny nose, eye irritation, and fever, but complications can include ear infections, pneumonia, seizures, brain damage, and death.
Mumps is a viral disease causing fever, headache, muscle pain, loss of appetite, and swollen glands, especially in the neck.
Rubella, also called German measles, is a viral disease causing rash, arthritis, and mild fever. If a pregnant woman gets rubella it can cause serious birth defects or miscarriage.
The combination vaccine is live and recommended at 12-15 months with a booster at 4-6 years.
Effectiveness: Measles: 95% with one dose, 99% with two; Mumps: 88%; Rubella: at least 90%
Duration of Protection: Lifelong in most people. Some waning can occur but is not usually enough to make
Vaccine Complications and Risks: Fever, mild rash, and swelling of the glands in cheeks or neck. A fever-caused seizure can occur in 1 of 3,000 doses, and a condition of low platelets (called idiopathic thrombocytopenic purpura) can occur in 1 in 30,000 but usually goes away on its own and is also caused by the measles infection itself. (In the rare cases where it does not, removal of the spleen is the treatment, but this is extremely rare in children.) A serious allergic reaction may occur in 1 in a million.
People with immune-compromised systems can, in extremely rare circumstances, develop a disease called inclusion body encephalitis from the MMR vaccine, but the measles infection can also cause this.
Disease Complications and Risks: Approximately 1 in 1,000 children with measles will die, and approximately 1 in 1,000 will develop encephalitis that can lead to brain damage. Any person who becomes sick with measles is also at risk for an extremely rare condition called SSPE (subacute sclerosing panencephalitis). This chronic, progressive encephalitis is nearly always fatal and occurs in appeoximately 1 in 10,000 people who have measles, but it can develop up to six years after a person’s infection. Mumps can cause sterility in boys, and congenital rubella can cause various birth defects.
Additional Considerations: Measles is the most contagious circulating human disease on the planet – 90% of unprotected individuals who are exposed to the virus will become infected, and the airborne virus lingers in the air for up to two hours. Each individual infects approximately 12 to 18 others. However, the vaccine is not given before 1 year old because the antibodies a mother passes on to her infant during pregnancy can interfere with the immune response if the vaccine is given earlier.
It’s a bit ironic that the vaccine that was initially fraudulently linked to autism is the only one that protects against a disease – congenital rubella – that is one of the few known causes of autism.
General Info: Human papillomavirus (HPV) is the most common sexually transmitted virus in the US. Although most HPV infections clear on their own, some persist and can cause cervical, vaginal, vulvar, penile, anal, or head and neck cancers. HPV can also cause gential warts. An estimated 20 million people in the US are currently infected, with more than 6 million new cases occurring each year. Infection occurs soon after losing one’s virginity, with up to 64% of teen girls infected.
The two current HPV vaccines in the U.S. are the two-strain vaccine Cervarix, which protects against two strains that cause cervical cancer, and the four-strain vaccine Gardasil, recommended for males and females, which protects against two cancer-causing strains and two warts-causing strains.
The FDA approved a 9-strain vaccine (Gardasil 9) in late 2014, which should be available in mid-2015. The HPV vaccine is recommended as a 3-dose series at age 11-12, with two months between the first and second dose and the third given six months after the first.
Effectiveness: Efficacy: 95-99%
Duration of Protection: It’s only been available since 2006, and no waning has been seen yet.
Vaccine Complications and Risks: Pain, redness, and swelling at the injection site as well as fever and headache. Although fainting has occurred, it happened just as often with the placebo as with the vaccine.
Disease Complications and Risks: More than 11,000 cases of cervical cancer were diagnosed in the US in 2011, nearly 4,000 women died of the cancer that year.
Additional Considerations: The HPV vaccine has previously been linked to blood clots, but this link was actually related to other factors, such as smoking and birth control pills, in the girls who received it. There have been false media reports that the HPV vaccine can cause death or neurological problems, but there is no evidence for this. It has one of the lowest rates of adverse events related to the vaccine on the entire schedule, and it has been shown multiple times not to increase girls’ or boys’ likelihood of having sex earlier. The vaccine has to be given before a person is infected because it won’t work after someone is already infected. In addition, a person can become infected again and again with different strains.
General Info: Bacterial infections caused by Neisseria meningitides can cause severe, life-threatening infections of the blood stream or membranes surrounding the brain (called meningococcal meningitis) and can result in deafness, brain damage, loss of limbs, and death.
Meningococcal vaccines have been available since 1974, and several different formulations are available but recommended for different age groups. The two main vaccines (Menactra and Menveo) protect against four types of the bacteria (A, C, W and W-135). Menactra can be given to those aged 9 months to 55 years, and Menveo is approved for those 2-55 years. A new vaccine specifically for type B was approved by the FDA in late 2014, but has not yet been recommended for routine use. Two doses of either vaccine are recommended for all adolescents: 11-12 with a booster at 16.
Some infants should receive Menactra, including those who don’t have a functional spleen or who are immunocompromised. Your doctor can explain more.
Effectiveness: approximately 80-85% within 3-4 years (2011)
Duration of Protection: Antibodies start to decay after 3-5 years, but cases among vaccinated individuals are very rare.
Vaccine Complications and Risks: Redness and pain at injection site and mild fever, headache, or generally not feeling well.
Disease Complications and Risks: As the number one cause of meningitis in children 2-18, meningococcal only causes 1,000-1,200 cases per year in the U.S., but the disease is severe. Even with treatment, 10-15 will die up to 20% of survivors may lose limbs, become deaf, or suffer seizures or strokes. The disease progressively very quickly – it can often move from the first symptoms to death in less than 48 hours.
Additional Considerations: This disease presents a greater risk in places where individuals live closely together, such as college campuses or among military recruits.