Covid-19
| Disease:- | Coronavirus disease 2019 (COVID-19) |
|---|---|
| Virus strain:- | Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) |
| Source:- | Probably bats, possibly via pangolins |
| Location:- | Worldwide |
First report:- | China |
| Index case:- | Wuhan, Hubei, China |
| Date:- | 1 December 2019– present (6 months, 2 weeks and 3 days |
| Confirmed:- | 8,320,288 |
| Active:- | 3,837,055 |
| Recovered:- | 4,035,605 |
| Death:- | 447628 |
SIGNS AND SYMPTOMS
The usual incubation period (the time between infection and symptom onset) ranges from one to 14 days, and is most commonly five days.Some infected people have no symptoms, known as asymptomatic or presymptomatic carriers; transmission from such a carrier is considered possible. As at 6 April, estimates of the asymptomatic ratio range widely from 5 to 80 percent.
Symptoms of COVID-19 can be relatively non-specific; the two most common symptoms are fever (88 percent) and dry cough (68 percent). Less common symptoms include fatigue, respiratory sputum production (phlegm), loss of the sense of smell, loss of taste, shortness of breath, muscle and joint pain, sore throat, headache, chills, vomiting, coughing out blood, diarrhea, and rash.
Among those who develop symptoms, approximately one in five may become more seriously ill and have difficulty breathing.Emergency symptoms include difficulty breathing, persistent chest pain or pressure, sudden confusion, difficulty waking, and bluish face or lips; immediate medical attention is advised if these symptoms are present.Further development of the disease can lead to complications including pneumonia, acute respiratory distress syndrome, sepsis, septic shock, and kidney failure.
CAUSE
COVID-19 spreads primarily when people are in close contact and one person inhales small droplets produced by an infected person (symptomatic or not) coughing, sneezing, talking, or singing. The WHO recommends 1 metre (3 ft) of social distance;the U.S. CDC recommends 2 metres (6 ft).People can transmit the virus without showing symptoms, but it is unclear how often this happens.One estimate of the number of those infected who are asymptomatic is 40%.
People are most infectious when they show symptoms (even mild or non-specific symptoms), but may be infectious for up to two days before symptoms appear (pre-symptomatic transmission).They remain infectious an estimated seven to twelve days in moderate cases and an average of two weeks in severe cases.
When the contaminated droplets fall to floors or surfaces they can, though less commonly, remain infectious if people touch contaminated surfaces and then their eyes, nose or mouth with unwashed hands.On surfaces the amount of active virus decreases over time until it can no longer cause infection,[and surfaces are thought not to be the main way the virus spreads.It is unknown what amount of virus on surfaces is required to cause infection via this method, but it can be detected for up to four hours on copper, up to one day on cardboard, and up to three days on plastic (polypropylene) and stainless steel (AISI 304).Surfaces are easily decontaminated with house hold disinfectants which kill the virus outside the human body or on the hands.Disinfectants or bleach are not a treatment for COVID‑19, and cause health problems when not used properly, such as when used inside the human body.
Sputum and saliva carry large amounts of virus. Although COVID‑19 is not a sexually transmitted infection, kissing, intimate contact, and faecal-oral routes are suspected to transmit the virus.Some medical procedures are aerosol-generating,and result in the virus being transmitted more easily than normal.
COVID‑19 is a new disease, and many of the details of its spread are still under investigation.It spreads easily between people—easier than influenza but not as easily as measles.[Estimates of the number of people infected by one person with COVID-19 (the R0) have varied widely. The WHO's initial estimates of the R0 were 1.4-2.5 (average 1.95), however a more recent review found the basic R0 (without control measures) to be higher at 3.28 and the median R0 to be 2.79.
The virus may occur in breast milk, but it's unknown whether it's infectious and transmitted
DIAGNOSIS
COVID-19 can be provisionally diagnosed on the basis of symptoms and confirmed using reverse transcription polymerase chain reaction (RT-PCR) testing of infected secretions or CT imaging of the chest
Viral testing
The standard test for current infection with SARS-CoV-2 uses RNA testing of respiratory secretions collected using a nasopharyngeal swab, though it is possible to test other samples. This test uses real-time rRT-PCR which detects the presence of viral RNA fragments.
A number of laboratories and companies have developed serological tests, which detect antibodies produced by the body in response to infection.Several have been evaluated by Public Health England and approved for use in the UK.
Imaging
Characteristic imaging features on chest radiographs and computed tomography (CT) of people who are symptomatic include asymmetric peripheral ground-glass opacities without pleural effusions.The Italian Radiological Society is compiling an international online database of imaging findings for confirmed cases. Due to overlap with other infections such as adenovirus, imaging without confirmation by rRT-PCR is of limited specificity in identifying COVID-19. A large study in China compared chest CT results to PCR and demonstrated that though imaging is less specific for the infection, it is faster and more sensitive
PREVENTION
Strategies for preventing transmission of the disease include maintaining overall good personal hygiene, washing hands, avoiding touching the eyes, nose, or mouth with unwashed hands, and coughing or sneezing into a tissue, and putting the tissue directly into a waste container. Those who may already have the infection have been advised to wear a surgical mask in public.Physical distancing measures are also recommended to prevent transmission.Health care providers taking care of someone who may be infected are recommended to use standard precautions, contact precautions, and eye protection.
Many governments have restricted or advised against all non-essential travel to and from countries and areas affected by the outbreak.The virus has already spread within communities in large parts of the world, with many not knowing where or how they were infected.
Surfaces may be decontaminated with a number of solutions (within one minute of exposure to the disinfectant for a stainless steel surface), including 62–71 percent ethanol, 50–100 percent isopropanol, 0.1 percent sodium hypochlorite, 0.5 percent hydrogen peroxide, and 0.2–7.5 percent povidone-iodine. Other solutions, such as benzalkonium chloride and chlorhexidine gluconate, are less effective.The CDC recommends that if a COVID-19 case is suspected or confirmed at a facility such as an office or day care, all areas such as offices, bathrooms, common areas, shared electronic equipment like tablets, touch screens, keyboards, remote controls, and ATM machines used by the ill persons should be disinfected
Face masks and respiratory hygiene
Recommendations for wearing cloth masks have been a subject of debate.The WHO originally recommended that healthy people wear masks only if they are at high risk, such as those who are caring for a person with COVID-19.China and the United States, among other countries, have encouraged the use of face masks or cloth face coverings more generally by members of the public to limit the spread of the virus by asymptomatic individuals as a precautionary principle.Several national and local governments have made wearing masks mandatory.
Surgical masks are recommended for those who may be infected, as wearing this type of mask can limit the volume and travel distance of expiratory droplets dispersed when talking, sneezing, and coughing.
In June 2020, the WHO changed its policy on wearing face masks, saying they should be worn in public places in order to help to prevent the spread of COVID-19.
In June 2020, the WHO changed its policy on wearing face masks, saying they should be worn in public places in order to help to prevent the spread of COVID-19
Social distancing
Social distancing (also known as physical distancing) includes infection control actions intended to slow the spread of disease by minimising close contact between individuals. Methods include quarantines; travel restrictions; and the closing of schools, workplaces, stadiums, theatres, or shopping centres. Individuals may apply social distancing methods by staying at home, limiting travel, avoiding crowded areas, using no-contact greetings, and physically distancing themselves from others. Many governments are now mandating or recommending social distancing in regions affected by the outbreak. Non-cooperation with distancing measures in some areas has contributed to the further spread of the pandemic.
The maximum gathering size recommended by U.S. government bodies and health organisations was swiftly reduced from 250 people (if there were no known COVID-19 spread in a region) to 50 people, and later to 10. On 22 March 2020, Germany banned public gatherings of more than two people.A Cochrane review found that early quarantine with other public health measures are effective in limiting the pandemic, but the best manner of adopting and relaxing policies are uncertain, as local conditions vary.
Older adults and those with underlying medical conditions such as diabetes, heart disease, respiratory disease, hypertension, and compromised immune systems face increased risk of serious illness and complications and have been advised by the CDC to stay home as much as possible in areas of community outbreak.
In late March 2020, the WHO and other health bodies began to replace the use of the term "social distancing" with "physical distancing", to clarify that the aim is to reduce physical contact while maintaining social connections, either virtually or at a distance. The use of the term "social distancing" had led to implications that people should engage in complete social isolation, rather than encouraging them to stay in contact through alternative mean.Some authorities have issued sexual health guidelines for the pandemic, which include recommendations to have sex only with someone you live with, and who does not have the virus or symptoms of the virus.
Self-isolation
Self-isolation at home has been recommended for those diagnosed with COVID-19 and those who suspect they have been infected. Health agencies have issued detailed instructions for proper self-isolation
Many governments have mandated or recommended self-quarantine for entire populations.The strongest self-quarantine instructions have been issued to those in high risk groups. Those who may have been exposed to someone with COVID-19 and those who have recently travelled to a country or region with the widespread transmission have been advised to self-quarantine for 14 days from the time of last possible exposure.
MANAGMENT
Screening, containment and mitigation
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Strategies in the control of an outbreak are screening, containment (or suppression) and mitigation. Screening is done with a device such as a thermometer to detect the elevated body temperature associated with fevers caused by the Coronavirus.Containment is undertaken in the early stages of the outbreak and aims to trace and isolate those infected as well as introduce other measures to stop the disease from spreading. When it is no longer possible to contain the disease, efforts then move to the mitigation stage: measures are taken to slow the spread and mitigate its effects on the healthcare system and on society. A combination of both containment and mitigation measures may be undertaken at the same time. Suppression requires more extreme measures so as to reverse the pandemic by reducing the basic reproduction number to less than 1.
Part of managing an infectious disease outbreak is trying to delay and decrease the epidemic peak, known as flattening the epidemic curve.This decreases the risk of health services being overwhelmed and provides more time for vaccines and treatments to be developed.Non-pharmaceutical interventions that may manage the outbreak include personal preventive measures such as hand hygiene, wearing face masks, and self-quarantine; community measures aimed at physical distancing such as closing schools and cancelling mass gathering events; community engagement to encourage acceptance and participation in such interventions; as well as environmental measures such surface cleaning.
More drastic actions aimed at containing the outbreak were taken in China once the severity of the outbreak became apparent, such as quarantining entire cities and imposing strict travel bans.Other countries also adopted a variety of measures aimed at limiting the spread of the virus. South Korea introduced the mass screening and localised quarantines and issued alerts on the movements of infected individuals. Singapore provided financial support for those infected who quarantined themselves and imposed large fines for those who failed to do so. Taiwan increased face mask production and penalised hoarding of medical supplies.
Simulations for Great Britain and the United States show that mitigation (slowing but not stopping epidemic spread) and suppression (reversing epidemic growth) have major challenges. Optimal mitigation policies might reduce peak healthcare demand by two-thirds and deaths by half, but still result in hundreds of thousands of deaths and overwhelmed health systems. Suppression can be preferred but needs to be maintained for as long as the virus is circulating in the human population (or until a vaccine becomes available), as transmission otherwise quickly rebounds when measures are relaxed. Long-term intervention to suppress the pandemic has considerable social and economic costs.
Contact tracing
Contact tracing is an important method for health authorities to determine the source of infection and to prevent further transmission.The use of location data from mobile phones by governments for this purpose has prompted privacy concerns, with Amnesty International and more than a hundred other organisations issuing a statement calling for limits on this kind of surveillance.
Several mobile apps have been implemented or proposed for voluntary use, and as of 7 April 2020 more than a dozen expert groups were working on privacy-friendly solutions such as using Bluetooth to log a user's proximity to other cellphones. (Users are alerted if they have been near someone who subsequently tests positive.)
On 10 April 2020, Google and Apple jointly announced an initiative for privacy-preserving contact tracing based on Bluetooth technology and cryptography.The system is intended to allow governments to create official privacy-preserving coronavirus tracking apps, with the eventual goal of integration of this functionality directly into the iOS and Android mobile platforms.In Europe and in the U.S., Palantir Technologies is also providing COVID-19 tracking services.
Health care
Increasing capacity and adapting healthcare for the needs of COVID-19 patients is described by the WHO as a fundamental outbreak response measure. The ECDC and the European regional office of the WHO have issued guidelines for hospitals and primary healthcare services for shifting of resources at multiple levels, including focusing laboratory services towards COVID-19 testing, cancelling elective procedures whenever possible, separating and isolating COVID-19 positive patients, and increasing intensive care capabilities by training personnel and increasing the number of available ventilators and beds.In addition, in an attempt to maintain physical distancing, and to protect both patients and clinicians, in some areas non-emergency healthcare services are being provided virtually.
Due to capacity limitations in the standard supply chains, some manufacturers are 3D printing healthcare material such as nasal swabs and ventilator parts.In one example, when an Italian hospital urgently required a ventilator valve, and the supplier was unable to deliver in the timescale required, a local startup received legal threats due to alleged patent infringement after reverse-engineering and printing the required hundred valves overnight.On 23 April 2020, NASA reported building, in 37 days, a ventilator which is currently undergoing further testing. NASA is seeking fast-track approval.
TREATMENT
Antiviral medications are under investigation for COVID-19None has yet been shown to be clearly effective on mortality in published randomised controlled trials. However, remdesivir may affect the time it takes to recover from the virus. Emergency use authorisation for remdesivir was granted in the U.S. on 1 May, for people hospitalised with severe COVID.The interim authorisation was granted considering the lack of other specific treatments, and that its potential benefits appear to outweigh the potential risks.
Taking over-the-counter cold medications,drinking fluids, and resting may help alleviate symptoms.Depending on the severity, oxygen therapy, intravenous fluids, and breathing support may be required.
Other trials are investigating whether existing medications can be used effectively against COVID-19 or the immune reaction to it.On 16 June, the RECOVERY trial group released a statement that their preliminary results show low dose dexamethasone reduces mortality in patients receiving respiratory support, though previous reviews had suggested the use of steroids may worsen
CONCLUSION
The coronavirus disease continues to spread across the world following a trajectory that is difficult to predict. The health, humanitarian and socio-economic policies adopted by countries will determine the speed and strength of the recovery.The saftey of others are in our hand so prevention is better than cure
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