Associations have been shown between vitamin D levels and several respiratory tract infections suggesting that vitamin D deficiency may predispose to infection. Outbreaks of respiratory infections occur predominantly during months associated with lower exposure to the sun. While Institute of Medicine concluded in a 2011 report that the existing data were "not consistently supportive of a causal role" for vitamin D in reducing the risk of infection, [1] other reviews suggest that vitamin D supplementation can provide a protective role in reducing the incidence or severity of respiratory infections. [2] [3]
Beneficial effects of supplemental vitamin D for patients with COPD have also been shown. [4]
An inverse association between exposure to the sun and upper respiratory tract infections was first proposed in 1926 by Smiley, who theorized that seasonality of infection was caused by “disordered vitamine metabolism in the human...directly due to a lack of solar radiation during the dark months of winter.” [5] Studies of Dutch [6] and Russian [7] subjects have also indicated a correlation of ultraviolet light exposure and relative absence of infection. However, the seasonality of infections such as influenza may also be explicable by other factors. For example, low absolute humidity favours the survival of the influenza virus. [8] A review by authors from the University of Maryland School of Pharmacy suggested that while low-dose vitamin D supplementation was unlikely to be harmful, "sensible sun exposure" was "an inexpensive and enjoyable way" to ensure healthy levels of vitamin D. [9]
Evidence both for and against an association of vitamin D and respiratory infections has been reported. Early studies of vitamin D and mice came to different conclusions, with one group reporting a link and the other no link between deficiency and infection. [9] More recent studies of humans have also had divergent results. People with the lowest blood vitamin D levels reported having significantly more recent colds or cases of the flu chronic respiratory disorders, especially those who had pre-existing respiratory ailments [10] Children who took vitamin D3 supplements daily in winter were 42% less likely to get infected with seasonal flu than those who were given a placebo. [11] Mongolian schoolchildren who drank vitamin D fortified milk during winter reported having fewer colds than those who received non-fortified milk. [12] Another study found no effect of vitamin D supplementation on the incidence or severity of upper respiratory tract infections. Authors of one of the positive studies also stressed that their results would need to be confirmed in clinical trials before vitamin D could be recommended to prevent infections. [13]
The Institute of Medicine released a comprehensive, peer-reviewed report on calcium and vitamin D in 2011. The conclusion of the report was that the existing studies did not provide strong or consistent evidence for a link between vitamin D deficiency and respiratory tract infections. The authors stated that data from randomised controlled trials would be needed, showing a dose response to vitamin D supplementation, before recommendations could be considered. [1] In contrast, a more recent meta-analysis concluded "Vitamin D supplementation was safe and it protected against acute respiratory tract infection overall. Patients who were very vitamin D deficient and those not receiving bolus doses experienced the most benefit." [2]
Low serum levels of vitamin D appear to be a risk factor for tuberculosis. [14] However, supplementation trials showed no benefit. [15] [16] Vitamin D supplementation does not help prevent asthma attacks or alleviate symptoms. [17]
Proponents of the vitamin D hypothesis have recommended dietary supplements (5,000 International Units (IU)/day for adults and 1,000 IU/day for every 25 pounds of body weight in children) and suggested that larger doses (2,000 IU/kg/day for 3–4 days) could be used to treat influenza. [18] [19] It has been noted that large doses of vitamin D can lead to hypercalcemia and that "single megadoses" of vitamin D, while not especially harmful, may be associated with an increased risk of bone fractures. [9]
Ciprofloxacin is a fluoroquinolone antibiotic used to treat a number of bacterial infections. This includes bone and joint infections, intra-abdominal infections, certain types of infectious diarrhea, respiratory tract infections, skin infections, typhoid fever, and urinary tract infections, among others. For some infections it is used in addition to other antibiotics. It can be taken by mouth, as eye drops, as ear drops, or intravenously.
Asthma is a common long-term inflammatory disease of the airways of the lungs. Asthma occurs when allergens, pollen, dust, or other particles, are inhaled into the lungs, causing the bronchioles to constrict and produce mucus, which then restricts oxygen flow to the alveoli. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, coughing, chest tightness, and shortness of breath. These may occur a few times a day or a few times per week. Depending on the person, asthma symptoms may become worse at night or with exercise.
Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severity of the condition is variable.
The common cold or the cold is a viral infectious disease of the upper respiratory tract that primarily affects the respiratory mucosa of the nose, throat, sinuses, and larynx. Signs and symptoms may appear in as little as two days after exposure to the virus. These may include coughing, sore throat, runny nose, sneezing, headache, and fever. People usually recover in seven to ten days, but some symptoms may last up to three weeks. Occasionally, those with other health problems may develop pneumonia.
Cholecalciferol, also known as vitamin D3 or colecalciferol, is a type of vitamin D that is produced by the skin when exposed to UVB light; it is found in certain foods and can be taken as a dietary supplement.
Bronchiolitis is inflammation of the small airways also known as the bronchioles in the lungs. Acute bronchiolitis is caused by a viral infection, usually affecting children younger than two years of age. Symptoms may include fever, cough, runny nose or rhinorrhea, and wheezing. More severe cases may be associated with nasal flaring, grunting, or respiratory distress. If the child has not been able to feed properly due to the illness, signs of dehydration may be present.
An upper respiratory tract infection (URTI) is an illness caused by an acute infection, which involves the upper respiratory tract, including the nose, sinuses, pharynx, larynx or trachea. This commonly includes nasal obstruction, sore throat, tonsillitis, pharyngitis, laryngitis, sinusitis, otitis media, and the common cold. Most infections are viral in nature, and in other instances, the cause is bacterial. URTIs can also be fungal or helminthic in origin, but these are less common.
Procalcitonin (PCT) is a peptide precursor of the hormone calcitonin, the latter being involved with calcium homeostasis. It arises once preprocalcitonin is cleaved by endopeptidase. It was first identified by Leonard J. Deftos and Bernard A. Roos in the 1970s. It is composed of 116 amino acids and is produced by parafollicular cells of the thyroid and by the neuroendocrine cells of the lung and the intestine.
Oseltamivir, sold under the brand name Tamiflu among others, is an antiviral medication used to treat and prevent influenza A and influenza B, viruses that cause the flu. Many medical organizations recommend it in people who have complications or are at high risk of complications within 48 hours of first symptoms of infection. They recommend it to prevent infection in those at high risk, but not the general population. The Centers for Disease Control and Prevention (CDC) recommends that clinicians use their discretion to treat those at lower risk who present within 48 hours of first symptoms of infection. It is taken by mouth, either as a pill or liquid.
Lower respiratory tract infection (LRTI) is a term often used as a synonym for pneumonia but can also be applied to other types of infection including lung abscess and acute bronchitis. Symptoms include shortness of breath, weakness, fever, coughing and fatigue. A routine chest X-ray is not always necessary for people who have symptoms of a lower respiratory tract infection.
Management of tuberculosis refers to techniques and procedures utilized for treating tuberculosis (TB), or simply a treatment plan for TB.
Nutrition and pregnancy refers to the nutrient intake, and dietary planning that is undertaken before, during and after pregnancy. Nutrition of the fetus begins at conception. For this reason, the nutrition of the mother is important from before conception as well as throughout pregnancy and breastfeeding. An ever-increasing number of studies have shown that the nutrition of the mother will have an effect on the child, up to and including the risk for cancer, cardiovascular disease, hypertension and diabetes throughout life.
Megavitamin therapy is the use of large doses of vitamins, often many times greater than the recommended dietary allowance (RDA) in the attempt to prevent or treat diseases. Megavitamin therapy is typically used in alternative medicine by practitioners who call their approach orthomolecular medicine. Vitamins are useful in preventing and treating illnesses specifically associated with dietary vitamin shortfalls, but the conclusions of medical research are that the broad claims of disease treatment by advocates of megavitamin therapy are unsubstantiated by the available evidence. It is generally accepted that doses of any vitamin greatly in excess of nutritional requirements will result either in toxicity or in the excess simply being metabolised; thus evidence in favour of vitamin supplementation supports only doses in the normal range. Critics have described some aspects of orthomolecular medicine as food faddism or even quackery. Research on nutrient supplementation in general suggests that some nutritional supplements might be beneficial, and that others might be harmful; several specific nutritional therapies are associated with an increased likelihood of the condition they are meant to prevent.
Respiratory tract infections (RTIs) are infectious diseases involving the lower or upper respiratory tract. An infection of this type usually is further classified as an upper respiratory tract infection or a lower respiratory tract infection. Lower respiratory infections, such as pneumonia, tend to be far more severe than upper respiratory infections, such as the common cold.
Palivizumab, sold under the brand name Synagis, is a monoclonal antibody produced by recombinant DNA technology used to prevent severe disease caused by respiratory syncytial virus (RSV) infections. It is recommended for infants at high-risk for RSV due to conditions such as prematurity or other medical problems including heart or lung diseases.
Vitamin C megadosage is a term describing the consumption or injection of vitamin C in doses well beyond the current United States Recommended Dietary Allowance of 90 milligrams per day, and often well beyond the tolerable upper intake level of 2,000 milligrams per day. There is no strong scientific evidence that vitamin C megadosage helps to cure or prevent cancer, the common cold, or some other medical conditions.
Vitamin D deficiency or hypovitaminosis D is a vitamin D level that is below normal. It most commonly occurs in people when they have inadequate exposure to sunlight, particularly sunlight with adequate ultraviolet B rays (UVB). Vitamin D deficiency can also be caused by inadequate nutritional intake of vitamin D; disorders that limit vitamin D absorption; and disorders that impair the conversion of vitamin D to active metabolites, including certain liver, kidney, and hereditary disorders. Deficiency impairs bone mineralization, leading to bone-softening diseases, such as rickets in children. It can also worsen osteomalacia and osteoporosis in adults, increasing the risk of bone fractures. Muscle weakness is also a common symptom of vitamin D deficiency, further increasing the risk of fall and bone fractures in adults. Vitamin D deficiency is associated with the development of schizophrenia.
Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, along with numerous other biological functions. In humans, the most significant compounds within this group are vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol).
Drug repositioning is the repurposing of an approved drug for the treatment of a different disease or medical condition than that for which it was originally developed. This is one line of scientific research which is being pursued to develop safe and effective COVID-19 treatments. Other research directions include the development of a COVID-19 vaccine and convalescent plasma transfusion.
Convalescent plasma is the blood plasma collected from a survivor of an infectious disease. This plasma contains antibodies specific to a pathogen and can be used therapeutically by providing passive immunity when transfusing it to a newly infected patient with the same condition. Convalescent plasma can be transfused as it has been collected or become the source material for hyperimmune serum or anti-pathogen monoclonal antibodies; the latter consists exclusively of IgG, while convalescent plasma also includes IgA and IgM. Collection is typically achieved by apheresis, but in low-to-middle income countries, the treatment can be administered as convalescent whole blood.