Public health intervention : Screening and Vaccination

A public health intervention is any effort or policy that attempts to improve mental and physical health on a population level. Public health interventions may be run by a variety of organizations, including governmental health departments and non-governmental organizations (NGOs). Common types of interventions include screening programs,[1] vaccination,[2] food and water supplementation, and health promotion. Common issues that are the subject of public health interventions include obesity,[3] drug, tobacco, and alcohol use,[4] and the spread of infectious disease, e.g. HIV.[5]

A policy may meet the criteria of a public health intervention if it prevents disease on both the individual and community level and has a positive impact on public health.[6]

Types

Health interventions may be run by a variety of organizations, including health departments and private organizations. Such interventions can operate at various scales, such as on a global, country, or community level. The whole population can be reached via websites, audio/video messages and other mass media, or specific groups can be affected by administrative action, such as increasing the provision of healthy food at schools.

Screening

Screening refers to the practice of testing a set of individuals who meet a certain criteria (such as age, sex, or sexual activity) for a disease or disorder. Many forms of screening are public health interventions. For example, mothers are routinely screened for HIV and Hepatitis B during pregnancy. Detection during pregnancy can prevent maternal transmission of the disease during childbirth.[7]

Vaccination

Vaccination programs are one of the most effective and common types of public health interventions. Typically programs may be in the form of recommendations or run by governmental health departments or nationalised health care systems. For instance, in the U.S., the Center for Disease Control decides on a vaccination schedule, and most private health insurers cover these vaccinations. In the UK, the NHS both decides and implements vaccination protocols. NGOs also may be involved in funding or implementing vaccination programs; for instance Bill and Melinda Gates Foundation assists governments in Pakistan, Nigeria and Afghanistan with the administration of polio vaccination.[8]

Supplementation

Supplementation of food or water of nutrients can reduce vitamin deficiency and other diseases. Supplementation may be required by law or voluntary. Some examples of interventions include:

Behavioral

Interventions intended to change the behavior of individuals can be especially challenging. One such form is health promotion, where education and media may be used to promote healthy behaviors, such as eating healthy foods (to prevent obesity), using condoms (to prevent the transmission of STDs), or stopping open defecation in developing countries (see for example in India the campaign Swachh Bharat Mission).

The use of laws to criminalize certain behaviors can also be considered a public health intervention, such as mandatory vaccination programs[13][14] and criminalization of HIV transmission.[15][16][17] However, such measures are typically controversial, particularly in the case of HIV criminalization where there is evidence it may be counter productive.[15][16][17] Laws which tax certain unhealthy products may also be effective, although also not without controversy, and are sometimes called a “sin tax“. Examples include the taxation of tobacco products in the U.S. and New Zealand,[18] and sugared drinks in the UK.[19]

Evaluating efficacy

Evaluating and predicting the efficacy of a public health intervention, as well as calculating cost effectiveness, is essential. An intervention should ideally lower morbidity and mortality. Several systematic protocols exist to assist developing such interventions, such as Intervention Mapping.[20]

Screening

Screening, in medicine, is a strategy used to look for as-yet-unrecognised conditions or risk markers.[1][2][3] This testing can be applied to individuals or to a whole population. The people tested may not exhibit any signs or symptoms of a disease, or they might exhibit only one or two symptoms, which by themselves do not indicate a definitive diagnosis.

Screening interventions are designed to identify conditions which could at some future point turn into disease, thus enabling earlier intervention and management in the hope to reduce mortality and suffering from a disease. Although screening may lead to an earlier diagnosis, not all screening tests have been shown to benefit the person being screened; overdiagnosis, misdiagnosis, and creating a false sense of security are some potential adverse effects of screening. Additionally, some screening tests can be inappropriately overused.[4][5] For these reasons, a test used in a screening program, especially for a disease with low incidence, must have good sensitivity in addition to acceptable specificity.[6]

Several types of screening exist: universal screening involves screening of all individuals in a certain category (for example, all children of a certain age). Case finding involves screening a smaller group of people based on the presence of risk factors (for example, because a family member has been diagnosed with a hereditary disease). Screening interventions are not designed to be diagnostic, and often have significant rates of both false positive and false negative results.

Frequently updated recommendations for screening are provided by the independent panel of experts, the United States Preventive Services Task Force.[7]

 

Common programs

In many countries there are population-based screening programmes. In some countries, such as the UK, policy is made nationally and programmes are delivered nationwide to uniform quality standards. Common screening programmes include:

 

Vaccination

 

Vaccinations
Young girl about to receive a vaccine in her upper arm (48545990252).jpg

Girl about to be vaccinated in her upper arm

Vaccination is the administration of a vaccine to help the immune system develop protection 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.[1] The effectiveness of vaccination has been widely studied and verified.[2][3][4] Vaccination is the most effective method of preventing infectious diseases;[5][6][7][8] 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.[9]

The first disease people tried to prevent by inoculation was most likely smallpox, with the first recorded use of variolation occurring in the 16th century in China.[10] It was also the first disease for which a vaccine was produced.[11][12] Although at least six people had used the same principles years earlier, the smallpox vaccine was invented in 1796 by English physician Edward Jenner. He was the first to publish evidence that it was effective and to provide advice on its production.[13] Louis Pasteur furthered the concept through his work in microbiology. The immunization was called vaccination because it was derived from a virus affecting cows (Latin: vacca ‘cow’).[11][13] Smallpox was a contagious and deadly disease, causing the deaths of 20–60% of infected adults and over 80% of infected children.[14] When smallpox was finally eradicated in 1979, it had already killed an estimated 300–500 million people in the 20th century.[15][16][17]

Vaccination and immunization have a similar meaning in everyday language. This is distinct from inoculation, which uses unweakened live pathogens. Vaccination efforts have been met with some reluctance on scientific, ethical, political, medical safety, and religious grounds, although no major religions oppose vaccination, and some consider it an obligation due to the potential to save lives.[18] In the United States, people may receive compensation for alleged injuries under the National Vaccine Injury Compensation Program. Early success brought widespread acceptance, and mass vaccination campaigns have greatly reduced the incidence of many diseases in numerous geographic regions.

Vaccination and autism

The notion of a connection between vaccines and autism originated in a 1998 paper published in The Lancet whose lead author was the physician Andrew Wakefield. His study concluded that eight of the 12 patients (ages 3–10) developed behavioral symptoms consistent with autism following the MMR vaccine (an immunization against measles, mumps, and rubella).[111] The article was widely criticized for lack of scientific rigor and it was proven that Wakefield falsified data in the article.[111] In 2004, 10 of the original 12 co-authors (not including Wakefield) published a retraction of the article and stated the following: “We wish to make it clear that in this paper no causal link was established between MMR vaccine and autism as the data were insufficient.”[112] In 2010, The Lancet officially retracted the article stating that several elements of the article were incorrect, including falsified data and protocols. This Lancet article has sparked a much greater anti-vaccination movement, particularly in the United States. Even though the article was fraudulent and was retracted, 1 in 4 parents still believe vaccines can cause autism.[113]

To date, all validated and definitive studies have shown that there is no correlation between vaccines and autism.[114] One of the studies published in 2015 confirms there is no link between autism and the MMR vaccine. Infants were given a health plan, that included an MMR vaccine, and were continuously studied until they reached 5 years old. There was no link between the vaccine and children who had a normally developed sibling or a sibling that had autism making them a higher risk for developing autism themselves.[115]

It can be difficult to correct the memory of humans when wrong information is received prior to correct information. Even though there is much evidence to go against the Wakefield study and most of the co-authors publishing retractions, many continue to believe and base decisions off of it as it still lingers in their memory. Studies and research are being conducted to determine effective ways to correct misinformation in the public memory.[116] Since the Wakefield study was released over 20 years ago, it may prove easier for newer generations to be properly educated on vaccinations. A very small percentage of people have adverse reactions to vaccines, and if there is a reaction it is often mild. These reactions do not include autism.

Skin cancer

Skin cancers are cancers that arise from the skin. They are due to the development of abnormal cells that have the ability to invade or spread to other parts of the body.[10] There are three main types of skin cancers: basal-cell skin cancer (BCC), squamous-cell skin cancer (SCC) and melanoma.[1] The first two, along with a number of less common skin cancers, are known as nonmelanoma skin cancer (NMSC).[5][11] Basal-cell cancer grows slowly and can damage the tissue around it but is unlikely to spread to distant areas or result in death.[5] It often appears as a painless raised area of skin that may be shiny with small blood vessels running over it or may present as a raised area with an ulcer.[1] Squamous-cell skin cancer is more likely to spread.[5] It usually presents as a hard lump with a scaly top but may also form an ulcer.[2] Melanomas are the most aggressive. Signs include a mole that has changed in size, shape, color, has irregular edges, has more than one color, is itchy or bleeds.[3]

More than 90% of cases are caused by exposure to ultraviolet radiation from the Sun.[4] This exposure increases the risk of all three main types of skin cancer.[4] Exposure has increased, partly due to a thinner ozone layer.[5][12] Tanning beds are another common source of ultraviolet radiation.[4] For melanomas and basal-cell cancers, exposure during childhood is particularly harmful.[6] For squamous-cell skin cancers, total exposure, irrespective of when it occurs, is more important.[4] Between 20% and 30% of melanomas develop from moles.[6] People with lighter skin are at higher risk[1][13] as are those with poor immune function such as from medications or HIV/AIDS.[5][14] Diagnosis is by biopsy.[3]

Decreasing exposure to ultraviolet radiation and the use of sunscreen appear to be effective methods of preventing melanoma and squamous-cell skin cancer.[6][7] It is not clear if sunscreen affects the risk of basal-cell cancer.[7] Nonmelanoma skin cancer is usually curable.[5] Treatment is generally by surgical removal but may, less commonly, involve radiation therapy or topical medications such as fluorouracil.[1] Immunotherapy might be the only hope for individuals with multiple malignancies such as Xeroderma Pigmentosum and Gorlin syndrome.[15] Treatment of melanoma may involve some combination of surgery, chemotherapy, radiation therapy and targeted therapy.[3] In those people whose disease has spread to other areas of the body, palliative care may be used to improve quality of life.[3] Melanoma has one of the higher survival rates among cancers, with over 86% of people in the UK and more than 90% in the United States surviving more than 5 years.[16][17]

Skin cancer is the most common form of cancer, globally accounting for at least 40% of cancer cases.[5][18] The most common type is nonmelanoma skin cancer, which occurs in at least 2–3 million people per year.[6][19] This is a rough estimate, however, as good statistics are not kept.[1] Of nonmelanoma skin cancers, about 80% are basal-cell cancers and 20% squamous-cell skin cancers.[11] Basal-cell and squamous-cell skin cancers rarely result in death.[6] In the United States, they were the cause of less than 0.1% of all cancer deaths.[1] Globally in 2012, melanoma occurred in 232,000 people and resulted in 55,000 deaths.[6] White people in Australia, New Zealand and South Africa have the highest rates of melanoma in the world.[6][20] The three main types of skin cancer have become more common in the last 20 to 40 years, especially in those areas with mostly White people.[5][6]