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Vaccination is the administration of a vaccine to help the immune system develop immunity from a disease. Vaccines contain a microorganism or virus in a weakened, live or killed state, or proteins or toxins from the organism. In stimulating the body's adaptive immunity, they help prevent sickness from an infectious disease. When a sufficiently large percentage of a population has been vaccinated, herd immunity results. Herd immunity protects those who may be immunocompromised and cannot get a vaccine because even a weakened version would harm them. The effectiveness of vaccination has been widely studied and verified. Vaccination is the most effective method of preventing infectious diseases; widespread immunity due to vaccination is largely responsible for the worldwide eradication of smallpox and the elimination of diseases such as polio and tetanus from much of the world. However, some diseases, such as measles outbreaks in America, have seen rising cases due to relatively low vaccination rates in the 2010s – attributed, in part, to vaccine hesitancy. According to the World Health Organization (WHO), vaccination prevents 3.5–5 million deaths per year.
Measles is a highly contagious infectious disease caused by measles virus. Symptoms usually develop 10–12 days after exposure to an infected person and last 7–10 days. Initial symptoms typically include fever, often greater than 40 °C (104 °F), cough, runny nose, and inflamed eyes. Small white spots known as Koplik's spots may form inside the mouth two or three days after the start of symptoms. A red, flat rash which usually starts on the face and then spreads to the rest of the body typically begins three to five days after the start of symptoms. Common complications include diarrhea, middle ear infection (7%), and pneumonia (6%). These occur in part due to measles-induced immunosuppression. Less commonly seizures, blindness, or inflammation of the brain may occur. Other names include morbilli, rubeola, red measles, and English measles. Both rubella, also known as German measles, and roseola are different diseases caused by unrelated viruses.
The MMR vaccine is a vaccine against measles, mumps, and rubella, abbreviated as MMR. The first dose is generally given to children around 9 months to 15 months of age, with a second dose at 15 months to 6 years of age, with at least four weeks between the doses. After two doses, 97% of people are protected against measles, 88% against mumps, and at least 97% against rubella. The vaccine is also recommended for those who do not have evidence of immunity, those with well-controlled HIV/AIDS, and within 72 hours of exposure to measles among those who are incompletely immunized. It is given by injection.
Vaccine hesitancy is a delay in acceptance, or downright refusal, of vaccines despite the availability of vaccine services. The term covers outright refusals to vaccinate, delaying vaccines, accepting vaccines but remaining uncertain about their use, or using certain vaccines but not others. The scientific consensus that vaccines are generally safe and effective is overwhelming. Vaccine hesitancy often results in disease outbreaks and deaths from vaccine-preventable diseases. Therefore, the World Health Organization characterizes vaccine hesitancy as one of the top ten global health threats.
Claims of a link between the MMR vaccine and autism have been extensively investigated and found to be false. The link was first suggested in the early 1990s and came to public notice largely as a result of the 1998 Lancet MMR autism fraud, characterised as "perhaps the most damaging medical hoax of the last 100 years". The fraudulent research paper authored by Andrew Wakefield and published in The Lancet claimed to link the vaccine to colitis and autism spectrum disorders. The paper was retracted in 2010 but is still cited by anti-vaccinationists.
Health in the United States is the overall health of the population of the United States. Health may refer to "a state of complete physical, mental and social well-being and not merely the absence of disease and infirmity.", according to the World Health Organization (WHO). 78.7 was the average life expectancy for individuals at birth in 2017. The highest cause of death for United States citizens is heart disease. Infectious diseases such as sexually transmitted diseases impact the health of approximately 19 million yearly. The two most commonly reported infectious diseases include chlamydia and gonorrhea. The United States is currently challenged by the COVID-19 pandemic, and is 19th in the world in COVID-19 vaccination rates. All 50 states in the U.S. require immunizations for children in order to enroll in public school, but various exemptions are available by state. Immunizations are often compulsory for military enlistment in the United States.
Measles vaccine protects against becoming infected with measles. Nearly all of those who do not develop immunity after a single dose develop it after a second dose. When rate of vaccination within a population is greater than 92%, outbreaks of measles typically no longer occur; however, they may occur again if the rate of vaccination decrease. The vaccine's effectiveness lasts many years. It is unclear if it becomes less effective over time. The vaccine may also protect against measles if given within a couple of days after exposure to measles.
The 2009–2010 West African meningitis outbreak was an epidemic of bacterial meningitis which occurred in Burkina Faso, Mali, Niger, and Nigeria since January 2009, an annual risk in the African meningitis belt. A total of 13,516 people have been infected with meningitis, and 931 have died. Nigeria has been the most adversely affected, with over half of the total cases and deaths occurring in the nation. The WHO reported on 27 March 2009 that 1,100 had died and there were 25,000 suspected cases. It is the worst outbreak in the region since 1996, and a third of the world's emergency vaccine stockpile for the bacterial form has been consumed. The GAVI Alliance has been trying to secure more vaccines.
Warnings About Vaccination Expectations NZ (WAVESnz), formerly the Immunisation Awareness Society (IAS), is a New Zealand anti-vaccination lobby group.
The 2012–2013 Swansea measles epidemic began in November 2012 and was declared over on 3 July 2013. There were a total of 1,219 measles notifications in Swansea, Neath Port Talbot, Bridgend, Carmarthenshire, Ceredigion, Pembrokeshire and Powys, with 1,455 measles notifications for the whole of Wales, 664 of which were in Swansea alone. A total of 88 people were hospitalised for measles infection during the epidemic. One death was reported: a 25-year-old man with giant cell pneumonia brought on by measles infection died on 18 April 2013. The cost associated with treating the sick and controlling the outbreak exceeded £470,000 ($701,898).
Measles is extremely contagious, but surviving the infection results in lifelong immunity, so its continued circulation in a community depends on the generation of susceptible hosts by birth of children. In communities which generate insufficient new hosts the disease will die out. This concept was first recognized by Bartlett in 1957, who referred to the minimum number supporting measles as the critical community size (CCS). Analysis of outbreaks in island communities suggested that the CCS for measles is c. 250,000.
In early 2019, a measles outbreak occurred in the Portland metropolitan area, including the Clark County, Washington suburbs, in the United States. At the time, the outbreak was the largest outbreak in more than two decades; outbreaks in 2019 in areas including Brooklyn and Rockland County, New York have since seen far greater numbers of cases.
The 2019 Philippines measles outbreak began in early 2019. An outbreak of measles was officially declared in February 2019 in select administrative regions in Luzon and Visayas including Metro Manila by the Philippine government. The outbreak is attributed to lowered vaccination rates, from a high of 88% 10 to 15 years previous to 74% at the time of the outbreak, allegedly caused by the Dengvaxia controversy.
Measles was declared eliminated from the United States in 2000 by the World Health Organization due to the success of vaccination efforts. However, it continues to be reintroduced by international travelers, and in recent years, anti-vaccination sentiment has allowed for the reemergence of measles outbreaks.
The 2019–2020 New Zealand measles outbreak was an epidemic that affected New Zealand, primarily the Auckland region. The outbreak was the worst epidemic in New Zealand since an influenza epidemic in 1999, and is the worst measles epidemic since 1938.
Vaccination policy in the United States is the subset of U.S. health policy that deals with immunization against infectious disease. It is decided at various levels of the government, including the individual states. This policy has been developed over the approximately two centuries since the invention of vaccination with the purpose of eradicating disease from the U.S. population, or creating a herd immunity. Policies intended to encourage vaccination impact numerous areas of law, including regulation of vaccine safety, funding of vaccination programs, vaccine mandates, adverse event reporting requirements, and compensation for injuries asserted to be associated with vaccination.
In 2019, a measles epidemic broke out in the Democratic Republic of the Congo (DRC). The epidemic started in early 2019 in the southeast corner of the DRC and then spread to all provinces. By June 2019 the epidemic was reported to have exceeded the death toll of the concurrent Ebola epidemic. By April 2020, it had infected more than 341,000 people and claimed about 6,400 fatalities. This has primarily affected children under the age of five, representing 74% of infections and nearly 90% of deaths.
The 2019 Samoa measles outbreak began in September 2019. As of 6 January 2020, there were over 5,700 cases of measles and 83 deaths, out of a Samoan population of 200,874. Over three percent of the population were infected. The cause of the outbreak was attributed to decreased vaccination rates, from 74% in 2017 to 31–34% in 2018, even though nearby islands had rates near 99%.
The 2019 Tonga measles outbreak began in October 2019 after a squad of Tongan rugby players came back from New Zealand. The epidemic as of 8 December is currently ongoing. As of 5 January, there have been 612 cases of measles.
The Disneyland measles outbreak began at the Disneyland Resort, California, in December 2014, and spread to seven states in the United States, Mexico, and Canada, before it was declared over in mid-April 2015.
References
- ↑ "Vainquons Ensemble la Rougeole à Madagascar". Ministère de la Santé Publique. 1 March 2019. Retrieved 13 May 2019.
- ↑ "Madagascar measles epidemic kills more than 1,200 despite desire for vaccinations". The Associated Press. 14 April 2019. Retrieved 1 July 2019.
- ↑ "MAF Flights Support Measles Prevention in Madagascar". Globalnewspublisher.com. 28 May 2019. Retrieved 16 June 2019.
- ↑ Bezain, Laetitia (14 April 2019). "Measles outbreak kills more than 1200 in Madagascar". Associated Press. Retrieved 13 May 2019.
- 1 2 "Madagascar: Measles Outbreak - Oct 2018". Relief Web. March 2019. Archived from the original on 13 April 2020. Retrieved 13 May 2019.
- ↑ "Emergencies preparedness, response: Measles - Madagascar". World Health Organization. 17 January 2019. Archived from the original on 20 October 2019. Retrieved 15 May 2019.
- ↑ Mensah, K.; Heraud, J. M.; Takahashi, S.; Winter, A. K.; Metcalf, C. J. E.; Wesolowski, A. (2019-04-24). "Seasonal gaps in measles vaccination coverage in Madagascar". Vaccine. 37 (18): 2511–2519. doi:10.1016/j.vaccine.2019.02.069. ISSN 0264-410X. PMC 6466641 . PMID 30940486.