Diseases eliminated from the U.S. by vaccines

I'm still working on my pertussis vaccine post. I'm also preparing to give a presentation this week, so I decided to use the material for that presentation for a post here.

You may have heard about disease eradication. So far, smallpox is the only disease to have been eradicated. Guinea worm (not a vaccine-preventable disease) and polio eradication programs are ongoing.

Eradication means that the disease no longer occurs anywhere in the world. Smallpox was declared eradicated in 1980. Once a disease has been eradicated, there is no longer a need for control measures. Smallpox vaccines are no longer recommended for the general population. I was born before the beginning of the smallpox eradication program, so I have a smallpox vaccination scar; Holly, who was born after smallpox vaccination in the U.S. was stopped, does not.

Elimination means that a disease no longer occurs within a geographic area. Because there is a risk for the disease to be imported from an area where the disease still occurs, control measures must continue. Importation occurs when a person is infected with a pathogen (a disease-causing bacteria, virus, fungus, or parasite) in an area where that disease still occurs and then enters a country where the disease does not occur.

Diphtheria

• Prior to the introduction of the vaccine, there were more than 125,000 cases of diphtheria and 10,000 deaths from diphtheria every year in the U.S.
• Diphtheria was the leading cause of childhood death in Canada from 1921 to 1924
• The last outbreak of diphtheria in the U.S. was in Seattle, Washington from 1972 to 1982
• There has not been a case of diphtheria in the U.S. since 2003
• Outbreaks continue to occur in Africa, Eastern Europe, Latin America and Southeast Asia
• Cases of diphtheria have been imported to the U.S.

Measles

• Prior to the introduction of measles, there were 200,000 to 500,000 cases of measles in the U.S. every year
• Measles vaccine was license in the U.S. in 1963
• Thirty seven years later, measles was declared eliminated from the U.S.
• Outbreaks of measles continue to occur in countries where measles vaccination coverage is low
• Worldwide, there were 164,000 deaths from measles in 2008; down from 2.6 million in 1980
• Last year, there was a measles epidemic in Europe and cases of measles were imported by U.S. citizens traveling abroad

Poliomyelitis (polio)

Improvements in sanitation have generally resulted in reduction in communicable diseases. Paradoxically, improved sanitation resulted in polio epidemics. Polio had been a common infection in babies who were partially protected by maternal antibodies (passive immunity). The infection was usually mild or inapparent. With improved hygiene standards, polio became an infection of older children who were no longer protected by maternal antibodies.

• In 1952 there were 57,628 cases of polio in the U.S.
• The "Salk" (inactivated injected) polio vaccine was licensed in 1955
• The "Sabin" (live oral) polio vaccine was licensed in 1960
• Polio was declared eliminated from the U.S. in 1979.

Rubella

Rubella and congential rubella syndrome were the topic of one of my previous posts.

• Rubella vaccine was first license in the U.S. in 1969
• Rubella and congenital rubella syndrome were declared eliminated from the U.S. in 2004
• The same year, 9 cases of rubella and 4 cases of congenital rubella syndrome were imported to New Hampshire

It's important to remember why we vaccinate. Many people in this country, including doctors and nurses, have never seen these diseases. I saw measles when I worked in Ethiopia, and we conducted acute flaccid paralysis (AFP) surveillance for polio while I was there. I had a great aunt who, as the result of a childhood polio infection, spent most of her life in a wheelchair.

It's easy to forget how serious these diseases are. When immunization rates are high and the incidences of vaccine-preventable diseases are low, the side effects of vaccines become more apparent than the diseases they prevent, and people can begin to question the benefit of vaccines (See: Life cycle of an immunization program).

References

Centers for Disease Control and Prevention. (2005). Imported cases of congential rubella syndrome – New Hampshire, 2005. Morbidity and Mortality Weekly Report, 54(45), 1160-1161. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5445a5.htm.

Centers for Disease Control and Prevention. (2011). Diphtheria. In Manual for the surveillance of vaccine-preventable diseases (5^th Ed.). http://www.cdc.gov/vaccines/pubs/surv-manual/chpt01-dip.html.

Centers for Disease Control and Prevention. (2011). Measles imported by returning U.S. travelers aged 6-23 months, 2001-2011. Morbidity and Mortality Weekly Report, 60(13), 397-400. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6013a1.htm?s_cid=mm6013a1_w.

Dowdle W. R. (1998). The principles of disease elimination and eradication. Morbidity and Mortality Weekly Report, 48(SU01), 23-27. http://www.cdc.gov/mmwr/preview/mmwrhtml/su48a7.htm.

Gerson, A. A. (2009). Measles virus (rubeola). In Mandell, G. L., Bennett, J. E., & Dolin, R. (Eds.). Mandell, Douglas, and Bennett’s principles and practice of infectious diseases. (7th Ed.) [Electronic version].

MacGregor, R. R. (2009). Corynebacterium diphtheria. In G. L. Mandell, J. E. Bennett, & R. Dolin (Eds.), Mandell, Douglas, and Bennett's principles and practice of infectious diseases (7th ed.). [Electronic version].

Malonado, Y. A. (2009). Polioviruses. In S. S. Long (Ed.) Principles and practice of pediatric infectious diseases (3rd Ed.) [Electronic version].

Modlin, J. F. (2009). Poliovirus. In Mandell, G. L., Bennett, J. E., & Dolin, R. (Eds.). Mandell, Douglas, and Bennett’s principles and practice of infectious diseases. (7th Ed.) [Electronic version]

Overturf, G. D. (2009). Corynebacterium diphtheriae. In S. S. Long (Ed.) Principles and practice of pediatric infectious diseases (3rd ed.). [Electronic version]. Philadelphia: Elsevier.

Pertussis (whooping cough)

While working in Ethiopia, I was stopped dead in my tracks by a stridorous breath taken by a young child. Having been a nurse for 10 years, it was a sound that I associated with severe respiratory distress. Having lived most of my life in a country with high immunization rates, I did not immediately recognize that sound as the "whoop" of pertussis.

Pertussis means "violent cough." It is also called "whooping cough" because of sound made when a breath is taken after a fit (paroxysm) of coughing – the sound I heard for the first time in Ethiopia. To the Chinese, pertussis is known as the "100-day cough."

Those terms describe pertussis well. People with pertussis can cough hard enough to break ribs, rupture the diaphragm, or rupture blood vessels in the eyes, the brain, or skin.

The term "whooping cough" can be a little misleading because not everyone with pertussis will whoop. Because our airway is larger than that of a child, adults with pertussis may not whoop at the end of a coughing fit. Babies are also less likely to whoop and more likely to gasp, gag, turn blue, or stop breathing than older children or adults.

Pertussis is caused by a bacteria called Bordetella pertussis (which is related to B. bronchiseptica, the cause of "kennel cough" in dogs), which is transmitted by respiratory droplets. The bacteria adhere to and kill the ciliated cells that normally move mucus and foreign material out of the respiratory tract. B. pertussis also produces toxins that inhibit normal immune responses to infection.

There are three stages to pertussis:

1. Catarrhal stage (also known as the prodromal stage) begins 7 to 10 days after becoming infected with B. pertussis (incubation period). The symptoms during this stage are similar to other upper respiratory infections and include runny nose, red eyes, watery eyes, low grade fever, and an occasional cough. This stage lasts about 1 to 2 weeks.

2. Paroxysmal stage takes its name from the paroxysms (fits) of violent coughing. The person will cough repeatedly in a single breath, which is followed by the characteristic "whoop." Vomiting after a fit of coughing is common. The paroxysmal stage usually lasts from 1 to 6 weeks, but can last longer.

3. Convalescent stage. Recovery from pertussis can take months. Coughing fits become less frequent and less severe, but can also recur during the convalescent stage. Unlike older children and adults, coughing fits may become louder and more severe in babies during this stage.

Unfortunately, immunity to pertussis, either through vaccination or though natural infection, wanes over time. For this reason, adults are a reservoir for B. pertussis. An adult who has been vaccinated against pertussis or who had pertussis as a child can have mild pertussis and, without realizing it, can infect infants who have not received enough doses diphtheria, tetanus, and acellular pertussis (DTaP) vaccine to be immune.

Complications of pertussis include pneumonia, encephalopathy, and seizures, all of which are more common in infants less one year of age. In the U.S., pertussis occurs most frequently in children less than one year of age, and most deaths occur in babies 3 months of age and under.

Babies are frequently infected with B. pertussis by household contacts – sisters, brothers, grandparents, fathers - and mothers.

Next, I'll discuss pertussis vaccines and recommendations.

References:

Long, S. S. & Edwards, K. M. (2009). Bordetella pertussis (pertussis) and other species. In S. S. Long (Ed.) Principles and practice of pediatric infectious diseases (3rd ed.). [Electronic version].

Paddock, C. D., Sanden, G. N., Cherry, J. D., Gal, A. A., Langston, C., Tatti, K. M. et al. (2008). Pathology and pathogenesis of fatal Bordetella pertussis infection in infants. Clinical Infectious Diseases, 47(3), 328-338. http://cid.oxfordjournals.org/content/47/3/328.long.

Slack, M. P. E. (2010). Gram-negative coccobacilli. In J. Cohen, S. M. Opal, & W. G. Powderly (Eds.) Infectious diseases (3rd ed.). [Electronic version].

Verma, A. (2008). Infections of the nervous system. In W. G. Bradley, R. B. Daroff, G. M. Fenichel, & J. Jankovic (Eds.) Neurology in clinical practice (5th ed.) [Electronic version].

Waters, V. & Halperin, S. (2009). Bordetella pertussis. In G. L. Mandell, J. E. Bennett, & R. Dolin (Eds.), Mandell, Douglas, and Bennett's principles and practice of infectious diseases (7th ed.). [Electronic version].

Fetal cell cultures

Some vaccine viruses are grown on human fetal cell cultures. These include rubella, hepatitis A, varicella zoster virus (chickenpox and shingles vaccines), one of the inactivated polio vaccines, and one of the rabies vaccines. The cells originally came from two aborted fetuses. The virus used in rubella vaccine came from a third aborted fetus.

Viruses are not complete cells. They lack the cellular mechanisms they need to replicate. Viruses take over the protein-manufacturing processes of the cells they infect. Unlike bacteria, which only require nutrients and a suitable environment to grow, vaccine viruses must be grown on living cells. Viruses for influenza and yellow fever vaccines are grown in embryonated (fertilized) chicken eggs. Measles and mumps vaccine viruses are grown on chick embryo fibroblast cell culture.

In the past, rubella vaccines were grown on duck embryo, dog kidney, and rabbit kidney cell cultures. The current human diploid fibroblast vaccine was chosen because it is more effective than the previously licensed vaccines and because side effects occurred less frequently.

There are two human diploid cell cultures used to make vaccines. The first, WI-38 (Wistar Institute, Philadelphia) was created in 1961 from tissue from a fetus aborted in Sweden. The second cell line, MRC-5 (Medical Research Council) was created in Britain in 1966. Both WI-38 and MRC-5 are continuous cell lines that have been maintained since they were created. Neither of the abortions was performed for the purpose of creating the cell cultures. The third abortion from which the virus used to manufacture rubella vaccines was obtained was performed because the mother became infected with rubella during her pregnancy.

The viruses are separated from the cells during the manufacturing process. The vaccines do not contain cells from the cultures in which the viruses are grown.

Ethical issues regarding the use of these vaccines include double effect and cooperation.

The principle of double effect means that an action can have both good and bad results. In 1964 there was an epidemic of rubella in the United States that caused 20,000 cases of congenital rubella syndrome (CRS). Women who become infected with the rubella virus are counseled about the risks of birth defects from CRS and may be advised to consider abortion.

Because there is high measles, mumps, and rubella vaccine (MMR) coverage in this country, rubella and congenital rubella syndrome have been eliminated from the United States.

Daniel P. Maher (2002) compared the use of vaccines derived from fetal cell lines to transplanting organs from a murder victim. We would not expect the recipients of the donated organs to forgo the benefit they receive from the transplanted organs because of the act that made them available.

The principle of cooperation is more complicated. In short, a person who chooses to receive a vaccine from a fetal cell line can in no way contribute to abortions that were performed over 40 years ago. Because WI-38 and MRC-5 are continuous cell lines, using vaccines grown on these cell cultures does not create a demand for future abortions.

In response to the concerns of Catholic parents about the morality of using vaccines associated with abortion, the Pontifical Academy of Life (2005) wrote that parents are responsible for protecting their children against these diseases and that, until alternatives are available, parents are morally free to use vaccines with historical associations to abortion. With regards to rubella, the document includes the following statement:

This is particularly true in the case of vaccination against German measles, because of the danger of Congenital Rubella Syndrome. This could occur, causing grave congenital malformations in the foetus, when a pregnant woman enters into contact, even if it is brief, with children who have not been immunized and are carriers of the virus. In this case, the parents who did not accept the vaccination of their own children become responsible for the malformations in question, and for the subsequent abortion of foetuses, when they have been discovered to be malformed.

As a nurse, documentation of my immunization status has been a requirement for employment for the last 20 years. For Holly, protecting our future children from congenital rubella syndrome far outweighed any concerns we had about the vaccine's historical association with abortion.

Additional information:

• Immunization Action Coalition: Religious and ethical concerns resources
• Institute for Vaccine Safety: Religion and Vaccines
• National Catholic Bioethics Center: FAQ on the use of vaccines
• National Network for Immunization Information: Human fetal links with some vaccines

References:

Finn, T. M. & Egan, W. (2008). Vaccine additives and manufacturing residuals in United States-licensed vaccines. In S. A. Plotkin, W. A. Orenstein, & P. A. Offit (Eds.) Vaccines (5^th Ed.). [Electronic version].

Fischer, F. (2011). Ethical childhood immunization. Ethics & Medics, 36(3), 3-4.

Furton, E. J. (1999). Vaccines originating in abortion. Ethics & Medics, 24(3), 3-4.

Furton, E. J. (2004). Vaccines and the right of conscience. National Catholic Bioethics Quarterly, 4(1), 53-62.

Glatz, C. (2008). Vatican: Parents may allow kids to get vaccines linked to abortion. Catholic News Service.

Grabenstein, J. D. (1999). Moral considerations with certain viral vaccines. Christianity & Pharmacy, 2(2), 3-6.

Maher, D. P. (2002). Vaccines, abortion, and moral coherence. National Catholic Bioethics Quarterly, 2(1), 51-67.

Plotkin, S. A. & Reef, S. E. (2008). Rubella vaccine. In S. A. Plotkin, W. A. Orenstein, & P. A. Offit (Eds.) Vaccines (5th Ed.) [Electronic version]

Pontifical Academy of Life. (2005). Moral reflections on vaccines prepared from cells derived from aborted human foetuses.

Zimmerman, R. K. (2004). Ethical analysis of vaccines grown in human cell strains derived from abortion: arguments and Internet search. Vaccine, 22(31-32), 4238-4244.
doi:10.1016/j.vaccine.2004.04.034.

Rubella (German measles)

Holly is now in her second trimester and prettier than she's ever been!

There's still a lot more that I could say about influenza and flu vaccines but, for the time being, I'm going to move on to rubella, a vaccine-preventable disease that can have devastating effects if acquired during pregnancy.

Rubella is the R in TORCH; a group of infectious diseases that cause severe birth defects:

• Toxoplasmosis
• Other (syphilis, viruses)
• Rubella
• Cytomegalovirus
• Herpes simplex

Rubella is caused by a virus that is transmitted by respiratory droplets. Rubella means "little red" because a rubella rash is similar to that of measles, but not as severe.

Symptoms of rubella include:

• Rash that starts on the face a spreads to the rest of the body
• Swollen lymph nodes
• Low grade fever

Infants and children may have asymptomatic ("without symptoms") infection, but still be contagious to others.

Rubella is usually benign and self-limiting but can cause arthritis and arthralgia (pain in the joints), which is more common and worse in adults. Encephalitis occurs in about 1 in 5,000 cases, more commonly in adults than children.

Congenital rubella syndrome (CRS):

Congential rubella syndrome occurs when a woman becomes infected with the rubella virus during pregnancy. The outcome of CRS is worse when the infection occurs in the first trimester of pregnancy.

Congenital rubella syndrome is typically associated with cataracts, congenital heart defects, deafness, and mental retardation but any organ system can be damaged by the virus. Maternal rubella infection can result in miscarriage or stillbirth. Birth defects associated with CRS may be present at birth or may not become apparent until years later. Babies with CRS shed large amounts of rubella virus for months after birth.

Other conditions that can result from CRS include:

• Autism
• Endocrine disorders
• Failure to thrive
• Low birth weight
• Retinopathy

Measles, mumps, and rubella vaccine (MMR):

Because we have high MMR coverage in this country, rubella and congenital rubella syndrome have been eliminated from the United States. This means that, although cases of rubella are imported from outside of this country, the rubella virus no longer circulates among the U.S. population.

CDC, 2005

Like live attenuated influenza vaccine (LAIV), MMR is a live virus vaccine that should not be given to pregnant women because of a theoretical risk of infecting the baby with vaccine viruses. MMR is usually given to children, but may be given to adults. Women of childbearing age should wait one month after receiving MMR before getting pregnant. Holly received an MMR booster before we started trying to get pregnant.

So, what if you receive an MMR vaccination and then find out you're pregnant? Don't panic. It happens. The risk of harm to your baby from the vaccine is extremely low and there is no evidence that babies whose mothers received rubella vaccine during pregnancy have been harmed.

The most common side effects of MMR vaccine are pain and redness at the injection site. Other side effects of rubella vaccine are more common in adults than in children. They include mild rubella symptoms; fever, headache, joint pain/stiffness, rash, sore throat, and swollen lymph nodes.

More information:

Centers for Disease Control and Prevention

• Rubella
• Rubella (German Measles) Vaccination

National Network for Immunization Information

• Measles, Mumps, Rubella (MMR)

American College of Obstetrician and Gynecologists

• Reducing your risk of birth defects

References:

Badilla, X., Morice, A., Avila-Aguero, M. L., Saenz, E., Cerda, I., Reef, S., & Castillo-Solórzano, C. (2007). Fetal risk associated with rubella vaccination during pregnancy. Pediatric Infectious Disease Journal, 26(9), 830-835. doi:10.1097/INF.0b013e318124a9f4.

Berger, B. E., Navar-Boggan, A. M., & Omer, S. B. (2011). Congenital rubella syndrome and autism spectrum disorders prevented by rubella vaccination – United States, 2001-2010. BMC Public Health 11(340) http://www.biomedcentral.com/1471-2458/11/340.

Centers for Disease Control and Prevention. (1998). Measles, mumps, and rubella – vaccine use and strategies for elimination of measles, rubella, and congenital rubella syndrome and controls of mumps. recommendations of the Advisory Committee on Immunization Practices (ACIP). Morbidity and Mortality Weekly Report, 47(8), 1-57. http://www.cdc.gov/mmwr/preview/mmwrhtml/00053391.htm.

Centers for Disease Control and Prevention. (2001). Revised ACIP recommendation for avoiding pregnancy after receiving a rubella-containing vaccine. Morbidity and Mortality Weekly Report, 50(49), 1117. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5049a5.htm.

Centers for Disease Control and Prevention. (2005). Achievements in public health: elimination so rubella and congenital rubella syndrome – United States, 1969-2004. Morbidity and Mortality Weekly Report, 54(11), 279-282. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5411a5.htm.

Centers for Disease Control and Prevention. (2005). Imported cases of congential rubella syndrome – New Hampshire, 2005. Morbidity and Mortality Weekly Report, 54(45), 1160-1161. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5445a5.htm.

Gershon, A. A. (2009). Rubella virus (German measles). In Mandell, G. L., Bennett, J. E., & Dolin, R. (Eds.). Mandell, Douglas, and Bennett’s principles and practice of infectious diseases. (7th Ed.) pp. 2265-2288. [Electronic version] Churchill Livingstone.

Maldonado, Y. A. (2009). Rubella virus. In S. S. Long (Ed.) Principles and practice of pediatric infectious diseases (3rd Ed.) [Electronic version].

Plotkin, S. A. & Reef, S. E. (2008). Rubella vaccine. In S. A. Plotkin, W. A. Orenstein, & P. A. Offit (Eds.) Vaccines (5th Ed.) [Electronic version]