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, vaccination prevents 3.5–5 million deaths per year.
Measles is a highly contagious, vaccine-preventable 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.
Vaccine hesitancy is a delay in acceptance, or refusal, of vaccines despite the availability of vaccine services and supporting evidence. The term covers 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.
The Expanded Program on Immunization(EPI) in the Philippines began in July 1979. And, in 1986, made a response to the Universal Child Immunization goal. The four major strategies include:
- sustaining high routine Full Immunized Child (FIC) coverage of at least 90% in all provinces and cities;
- sustaining the polio-free country for global certification;
- eliminating measles by 2008; and
- eliminating neonatal tetanus by 2008.
A vaccination policy is a health policy adopted in order to prevent the spread of infectious disease. These policies are generally put into place by State or local governments, but may also be set by private facilities, such as workplaces or schools. Many policies have been developed and implemented since vaccines were first made widely available.
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.
Dengue vaccine is a vaccine used to prevent dengue fever in humans. Development of dengue vaccines began in the 1920s, but was hindered by the need to create immunity against all four dengue serotypes.
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. Due to the development of vaccination against measles, the world has seen a 99% decrease in measles related cases compared cases before the vaccine was developed.
The Dengvaxia controversy occurred in the Philippines when the dengue vaccine Dengvaxia was found to increase the risk of disease severity for some people who had received it.
In early months of 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 measles outbreaks refer to a substantial global increase in the number of measles cases reported, relative to 2018. As of April 2019, the number of measles cases reported worldwide represented a 300% increase from the number of cases seen in the previous year, constituting over 110,000 measles cases reported in the first three months of 2019. In the first half of 2019, the World Health Organization received reports of 364,808 measles cases from 182 countries, up 182% from the same time period of 2018 when 129,239 confirmed cases were reported by 181 countries.
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 of the United States is the subset of U.S. federal 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.
The 2019–2021 polio outbreak in the Philippines was an epidemic. For the previous 19 years, the Philippines was free of any polio-related diseases. On September 14, 2019, the disease began to resurface through a positive test result done to a 3-year-old girl from Mindanao. After the confirmation of a second case from tests done on a 5-year-old boy, the government of the Philippines publicly declared a polio outbreak on September 19, 2019. On June 11, 2021, the WHO announced that the outbreak has ended.
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. As of 5 January, 2020, there have been 612 cases of measles.
The COVID-19 vaccination program in the Philippines is an ongoing mass immunization campaign against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), in response to the ongoing pandemic in the country. The vaccination program was initiated by the Duterte administration on March 1, 2021, a day after the arrival of the country's first vaccine doses which were donated by the Chinese government.
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.
