A LITERATURE REVIEW ON COVID-19.

Abstract:

The outbreak of COVID 19 in Dec 2019 was initially thought of pneumonia. Later after inoculation and further studies of sign symptoms and its heinous outcomes revealed it to be of SAR-CoV the beta strain of coronavirus named severe acute respiratory syndrome coronavirus 2 that resulted in infecting the lower respiratory regions. Leads to extreme shortness of breath and even death. This outrage brought about enormous human life and economic as well as social loss to mankind rising death toll in millions, its subject to be the most deadly viral disease of 21st century till yet. The world economic forum on every ground supported and valued each stance for the redresses and treatment of COVID 19. Leading the high financial supporters to work hard enough for the vaccine formulation. However as being an RNA virus it manipulates its genetics rapidly and makes it almost impossible for the next varied strain to be targeted by the same vaccine. It’s structurally like crown with spikes on it. That get it attached to the host cell. It was identified in 2019 however documented COVID 19 pandemic in Feb. 2020 by the World Health Organization.

Introduction:

Following the 1918 flu pandemic, COVID-19 is the sixth pandemic to strike people globally. The coronavirus illness is a highly contagious and pathogenic viral infection brought on by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has had a devastating impact on humans and resulted in a significant loss of life globally. According to genomic research, severe acute respiratory syndrome and SARS-CoV-2 are phylogenetically linked [1].

SAR-CoV-2 is thought to have evolved from an animal coronavirus through spillover and later picked up the capacity for human-to-human transmission. The primary cause of these traits is that the coronavirus is extremely infectious, spreads quickly, and is constantly evolving in the human population [2]. So it’s plausible that the virus entered humans and then, as it spread to other individuals, adapted to take on the traits that allowed it to spread so swiftly [3].

Using phylogenetic research, the worldwide Council on Taxonomy of Viruses gave the corona virus the formal name severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The term “coronavirus” comes from the recognisable spikes with rounded tips that adorn their surface and give them a corona-like look. Positive-sense single-stranded RNA is the nucleic acid material found in coronaviruses, which are very small (65–125 nm in diameter). Between 26 to 32 kbs in length, enveloping spherical particles [4]. The coronavirus family has four subgroups: alpha (a), beta (b), gamma (c), and delta (d) coronaviruses [5].

HISTORY OF COVID-19 VIRUS:

A new acute respiratory syndrome coronavirus called SARS-CoV-2 is responsible for the severe acute respiratory syndrome.

On December 31, 2019, Wuhan City’s pneumonia outbreak was formally reported to the World Health Organization (WHO). On January 5, 59 instances were known, although none of them were fatalities. The WHO was informed of 282 confirmed instances ten days later, four of which were in Thailand, South Korea, and Japan. Six individuals had died, 51 had serious illnesses, and 12 were in critical condition in Wuhan. The culprit virus was discovered on January 7 and its genome was released on January 12. Hence, a new virus was the root cause of the severe acute respiratory illness that later became known as COVID-19 [6]. A novel coronavirus, subsequently known as MERS-CoV, was discovered in 2012 by researchers at Erasmus Medical Centre and their associates. It was identified from a Saudi Arabian male who had renal failure and pneumonia. A team of researchers from the University of Hong Kong finds the coronavirus HKUI in samples taken from two pneumonia patients in 2005. Researchers at the Erasmus Medical Center in the Netherlands report identifying the NL63 coronavirus from a youngster who had pneumonia in 2004. An international team of experts says that the 2003 SARS outbreak, which started in southern China at the end of 2002, is brought on by a recently discovered human corona virus. Eight scientists who had just photographed coronaviruses for the first time suggested in a 1968 letter to Nature that a new class of viruses known as coronaviruses should be used to describe freshly identified viruses. because the exterior surface of these viruses has spikes that resemble crowns. Researchers at the National Institute of Allergy and Infectious Diseases claim growing a novel human virus with a similar shape in 1967 using the same culture techniques that B814 did. The virus is known as OC43. The University of Chicago’s Dorothy Hamre and John Procknow disclose a virus that they obtained from a medical student who had the flu in 1966. They gave 229E a name. which set this respiratory virus apart from others. Researchers from the Wiltshire Common Cold Research Center in the United Kingdom report growing the virus B814 in 1965.to grow another new human virus with a similar morphology. They name the virus OC43. In 1966, Dorothy Hamre and John Procknow of the University of Chicago describe a virus, which they isolated from a medical student with a Cold. And they named 229E.Which is distinct from other respiratory viruses. In 1965, Researchers at the Common Cold Research Unit in Wiltshire, UK report cultivating virus, B814, from a cold-ridden child. They claim that the pathogen has little connection to the human respiratory system.

ORIGIN AND SPREAD:

The COVID-19 virus, often known as SARS-COV-2 (severe acute respiratory syndrome coronavirus-2), is a pneumonia-like illness [7].

It is a beta-coronavirus, this disease. There are now roughly six virus CoVs that are human-susceptible. Four of them often produce mild respiratory symptoms similar to the common cold and have minimal pathogenicity. The other two, SARS-CoV and MERS-CoV, produce extremely serious and even deadly respiratory diseases. It’s interesting to note that bat CoVRsTG13 and SARS-CoV-2 share 96.2% of their genomic sequences. Although it resembles SARS-CoV by 79.5 According to the genome sequences, it is possible to conclude that the bat is serving as the founding host for the virus.

The capital city of Hubei province, Wuhan, China, was where the infectious illness that causes severe acute respiratory syndrome (SARS) was found and diagnosed [8]. In December 2019, the sickness begins to spread from China. There were a lot of people in Wuhan City who had acute pneumonia from unknown causes. On December 31, 2019, China notified WHO of the epidemic. By matching the genome sequence of the virus with the genome sequence of the bat, the virus was recognised as a coronavirus. Due to the positive COVID test results from seafood, Huanan Seafood businesses were forced to close on January 1st, 2020. Samples were taken from the items on the market.

and the animals that had COVID-19 good results. Due to the influx of people on New Year’s Day, the first mortality case was recorded on January 11. As the population has congregated together and the illness is communicable, the possibility of a pandemic has increased. Restriction and lockdown measures were put in place as soon as the outbreak began. Nonetheless, the virus spread from Wuhan to neighbouring cities in the province of Hubei. The virus crossed the border on January 23rd, and cases were soon discovered in Thailand, South Korea, and Japan. 3 March 2020 had a recorded 96,000 cases. of which 80,000 are from China. Other nations including Iran, South Korea, and Italy saw a sharp increase in the number of cases. China now has the fewest instances compared to other nations. The epidemic is virtually under control as of right now [9].

Clinical features and characteristics:

Studying the current epidemiology of COVID-19. Most of the people had close contact with the COVID-19 patients or their traveling record to Wuhan or Hubei in China [10].

COVID-19 an acute respiratory infectious disease spreads through respiratory tract, by droplets or respiratory secretions. On 10 February 2020, SARS-CoV-2 was isolated from fecal swabs of pneumonia patient, which was a critical case in the Fifth Affiliated Hospital, Sun Yat-sen University, Guangdong, China. Similarly, the presence of SARS-CoV-2 in fecal swabs and blood, by Zhang et al, indicates the possibility of different route transmission [11]. 5 days are the median time from symptoms and signs to the well-developed phase of pneumonia [12]. Looking to the current epidemiological study, 1-14 days are the incubation time, majorly 3-7 days. The disease become lethal during their last period [13]. The clinical feature of 2019-nCoV is most likely to SARS-CoV and the symptoms of these include headache, dizziness, abdominal pain, diarrhea, nausea, and vomiting. The report of the first 425 verified cases in Wuhan had symptoms like fever, dry cough, myalgia, and fatigue. 75% cases have bilateral pneumonia.

COVID-19 patients with upper respiratory tract have signs and symptoms include rhinorrhea, sneezing, or sore throat, are lesser than lower respiratory tract. Meaning that virus is happy in the lower respiratory tract. Both pregnant and non-pregnant have same characteristics. COVID-19 patients can start severe problems like hypoxemia, acute ARDS, Arrythmia, shock, acute cardiac injury, and acute kidney injury [14]. The severity rate varies from place to place. Like in Wuhan the cases were severe and fatal than those which are found in Hubei province [15]. The disease is contagious and spread fast in humans, specifically in elders and older with already present disease [16].

COVID-19 patient age and sex; The data released by Chinese National Reporting System showcasing that the median age of verified cases were 51 years of which 77.8% were at the age of 30-69, in which the percentage of male patients were 51.1% [17].

Diagnosis of COVID-19:

After the outbreak of COVID-19 in late 2019, governments banned public gatherings and made rules for social distancing in order to avoid the exponential spread of infection [18]. In addition, for the proper and efficient diagnosis of COVID-19 and to differentiate it from seasonal flu which may affect the proper therapeutic procedure to treat infected patient, scientists were pushed to develop highly reliable and effective diagnostic procedures [19]. In this regards several diagnostic procedures and techniques have been validated by the international regulatory agencies but still there is ambiguity about the correct test for investigation purposes or considering patient medical history for proper diagnosis [20].

In order to monitor the epidemiology of infection and screen the immunized population, population screening strategies were developed. For this purpose 168 immunoassays, 192 PCR based methods, 3 next generation sequencing based methods were approved by FDA and CE-IVD which made the selection of proper diagnostic method more complicated [21]. Further-more several parameters should be kept in mind for efficient diagnostic test. It must be rapid, repeatable, and inexpensive, carried-out by the available technologies at diagnostic centers and should have high sensitivity and specificity values [22]. Three types of tests: Molecular RT-PCR swab test; Rapid antigen or antibody tests and Serological tests have been developed to full-fill the above requirements. The kits, reagent and molecular probes used for these diagnostic procedures should be approved by EMA (Europe), CDC, WHO and FDA (USA) [23]. In addition to the afore mentioned three approaches, viral culture and next generation sequencing methods were used for identification of viral protein structure, etiological agents of infection; understanding mechanism of action and mode of transmission and for development of clinical approaches and diagnostic tools[24]. Clinical investigations and radiological imaging techniques played a vital role in early phases of pandemic when no serological and molecular techniques were developed for diagnosis [25].

Despite all these techniques if we did not consider the type if test to be used , type of sample for analysis and timing of test then all efforts would be fruitless. So, for accurate diagnosis correct test, best sample at precise time should be analyzed [26, 27]. The accuracy of molecular and serological test is low, if performed before the onset of symptoms because viral load and antibodies are not in sufficient quantity [28, 29]. Moreover, the accuracy of molecular and serological depends upon the quality of sample collected. Technical trouble shooting will occur by incorrect handling of sample, poor quality kits and contamination with inhibitors etc. [30].

Now have a look at various diagnostic procedures:

1) RT-PCR molecular test: It is the most efficient and reliable technique used for COVID-19 diagnosis [31]. Different primers and probes specific for different regions of COVID-19 genome like RdRP coding genes, N genes and S genes etc are used for differential diagnosis between COVID-19 and other pathologies like seasonal flu etc [32, 33]. CDC has also approved three primer pairs, two falling in N gene region and one in RdRP gene region [34].

As mentioned earlier EMA and FDA has approved 192 and 235 PCR based methods in order to diagnose COVID-19 RNA [35]. COVID-19 is positive stranded RNA virus with a total genome of 29,903 bp in length. All the approved RT-PCR based targets 2 to 3 regions of RNA.

Sample collected from BALF is considered vital for diagnosis but it can also be collected from other respiratory sources such as nasopharyngeal and oropharyngeal swabs which contain sufficient quantity of viral load for viral RNA extraction and amplification [36]. After collection of sample from nasopharyngeal swabs or BALF the RNA is extracted by using WHO approved kits and lysing analytes. Then RNA is converted to cDNA using RdRP. After formation of cDNA different targeted regions are amplified for which TaqMan probes are used for detection. Fluorescent signals produced by the TaqMan probes are proportional to the amplified product, though they are used for qualitative analysis only [37, 38]. This molecular based testing procedure takes 4 to 8 hours depending upon the type of protocol used one-step or two-steps. Due to less diagnostic time it allows us to quarantine the infected person in time and prevent spreading of infection [39, 40]. RT-PCR also provide 48-96 wells platform which reduce the time, cost of apparatus required and procedural errors which may occurred if the samples are tested individually [41].

RT-PCR based diagnostic method has an upper hand on other strategies due to its low cost, commercial availability of RT-PCRs, easy execution strategies [42]. It also ensures the low limit of detection (LoD 0.3 to 100 copies/micro liter) of SARS-CoV-2 RNA [43, 44]. Although RT-PCR method is the most reliable methods but it also have some limitations: low sensitivity to incorrectly obtained samples, interference of inhibitors present in samples or added during handling process, and sensitivity towards the pre-analytical and analytical bias during collection, storage and handling [45, 46]. These are the limitations which may results in false-negative or false-positive diagnosis.

In order to overcome these limitation the WHO has given some directions such as: the test should be repeated and done with two different samples taken from different source or from same source with time difference. In addition to it WHO has given direction about the 2 to 3 viral genes, human control genes to be tested and specific positive and negative controls which shows the accuracy of test results affected by the contaminations and inhibitors added during handling [47].

2) Rapid antigen and antibody test:

It is used to cope with recurrent waves of COVID-19 infection frequent and fast diagnosis in most populated places like factory and schools etc. In this test viral antigens and anti-SARS-CoV-2 antibodies are detected in saliva, blood samples and respiratory track lining swabs [48].

These both tests works on the principle of lateral flow immunoassay (LFIA).

In rapid antigen test the sample and buffer is loaded in sample well of the strip. The sample containing viral antigen (nucleocapsid or spike proteins) moves towards the conjugated pad by capillary action. Conjugated pads contain anti-SARS-CoV-2 antigen conjugated antibodies and conjugated control rapid antibodies. Anti-SARS-CoV-2 antibodies bounds with the viral antigen and moves towards test line. At test line the complex of conjugated antibody and viral antigen gets attached to immobilized antibodies specific for viral antigen. This whole complex at the test line produces a colorimetric reaction which indicates the positivity of test. The conjugated control rapid antibodies moves further along with buffer and complex with anti-control rapid antibodies giving rise to colorimetric reaction shows that strip is correct [49, 50].

In rapid antibody test the blood sample along with buffer is loaded in the sample well. The sample containing human antibodies IgG, IgM and IgA moves towards the conjugated pad.

Conjugated pad contain the gold tagged viral antigens and control rabbit antibodies. The human antibodies attaches with viral antigen and moves towards the test line where antigen-antibody complex bounds with the anti-human IgA,IgM and IgG antibodies giving rise to colorimetric reaction ,confirms the diagnosis of COVID-19 infection. The control rabbit antibodies moves further and complex with anti-control rabbit antibodies shows that the strip is working rightly [51].

Rapid antigen and antibody test costs low and is rapid as compared to RT-PCR test. It can be easily done at point-of-care within 30 minutes without complex instrumentation and sample processing [52]. It also gives information about the stage of infection: in case of no infection only control line is stained; in case of resent infection the IgG and IgM bands get stained and in case of ongoing infection only IgG band get stained along with control line.

Despite its advantages it has certain limitations: It has low sensitivity and specificity of 56.2% and 99.5% respectively [53]. It is not possible to predict about the ongoing infection or the infection has ended because the antibodies can persist for long time in body [54]. It is impossible to diagnose recent infection because IgM and IgG antibodies are generated in third week of infection [55].

3) Immunoenzymatic seorological test: Immunoenzymatic serological test used for COVID-19 infection are usually based on indirect enzyme-linked immunosorbent assay (ELISA). Both ELISA indirect and sandwich tests can be used for COVID-19 diagnosis. It is mainly based on chemiluminescent microwell plate-based assay used for detection of human immunoglobulins; viral peptides and antigens by its attachment to detectable specific immunoglobulins and proteins [56].

ELISA indirect test: 96-well commercial available ELISA indirect is used for diagnosis of COVID-19. The micro-well contains immobilized viral antigen. First blood sample is added to each well. The anti-SARS-CoV-2 antibodies (IgG, IgM and IgA) present in the blood hybridizes with the viral antigen. Now the well are washed in order to remove the unbound antibodies and blood. After a series of washes a radiolabeled/fluorescent labelled anti-human antibodies ( anti-IgG, anti-IgA and anti-IgM) are added. These anti-human antibodies complexes with hybrid of antigen and anti-SARC-CoV-2 antibodies. This complex give rise to detectable signals which confirms the infection in a patient.

At present ELISA indirect test is used for the detection of IgM and IgG antibodies produced against COVID-19 [57].

ELISA sandwich method: In this method the antigen is sandwiched between the antibodies. First the patients serum containing the viral antigens like spike proteins is added to 96-well tray containing immobilized antibodies specific for antigen. The viral antigen hybridizes with anti-SARC-CoV-2 antibodies. Now after a series of washes conjugated antibodies also specific for viral antigen are added. Then the conjugated antibodies complexes with hybrid of viral antigen and anti-SARS-CoV-2 and results in visual results which confirms the presence and absence of infection in a sample. ELISA sandwich is mainly used for COVID-19 diagnosis [58]. ELISA is used for rapid testing of healthcare workers, factory workers and determination of immunological status and immune competence of patients against COVID-19 infection [59, 60]. ELISA cannot determine the infectious status of the patient. Even if a person is diagnosed positive with ELISA, RT-PCR based molecular test is necessary for confirmation.

Imaging techniques used for COVID-19 diagnosis: Initially when no molecular and serological lab technique were developed to diagnose the infection, the diagnosis was solely possible by performing different imaging techniques giving insight into respiratory track changes. Different imaging techniques used in COVID-19 detection are CT-scan, CXR, PET/CT, and lung ultrasound etc.

These imaging techniques were also diagnose asymptomatic patients who gave negative results with molecular and serological tests.

CT-scan can be to observe the presence of GGO, consolidation, numbers of lobes of lungs having GGO and consolidative opacities, extent of pleural changes such as pleural effusion and thickening etc [61, 62]. Chest CT was used to discriminate SARC-CoV-2 pneumonia from other viral and bacterial Multiple mottling, multiple GGO and sub-segmental areas of consolidation were often found in COVID-19 patient in contrary to it non-COVID-19 pneumonia showed patchy and density increasing shadows [63].
PET/CT is more sensitive and invasive imaging technique using specifically radio-tracers fluorodeoxyglucose F 18, for the detection of pulmonary infection, monitoring of infection progression and effects of treatment on infected patient. Studies suggested that there was an increase in uptake of fluorodeoxyglucose f 18 in pulmonary lymph nodes of COVID-19 infected patients [64]. Though PET/CT has more sensitivity than ordinary CT it also has some drawbacks like it is invasive procedure with radiotracers which may affect vital cells, it is more complex and time consuming than CT so it increases the chances of infection transmission to the health care persons [65].
Lung ultrasound is a non-invasive and radiation free imaging technique. As it is portable so it can be done on bedside of suspected patients in emergency rooms. Patients affected with COVID-19 shows irregular pleural lines besides small sub-pleural consolidations, having thick, confluent and irregular vertical artifacts [66]. In addition to it as it is non-invasive and radiation free procedure so it vital to use it for pregnant women screening as it reduce the chances of miscarriage.
During the early phases of COVID-19 chest X-rays were the cheapest and mostly used diagnostic tool as it is available at almost all health care centers. It was used for patients who showed moderate to severe symptoms accompanied by interstitial opacities, alveolar opacities etc [67]. Despite its low cast and wide availability and simplicity, it has low sensitivity, radiological image obtained were not clear and cause high radiations exposure. Therefore the CT- scan was widely used for diagnostic purposes.

TREATMENT:

Early on in the covid-19 pandemic, knowledge of it and its treatments were scarce. The use of antivirals or other medications to treat COVID-19 has not yet received approval. Yet since the pandemic spread so quickly, it was possible to treat COVID-19 using already-approved medications that have been shown to be effective against HIV, MERS, and SARS. After then, the tireless work of clinical researchers has led to a greater knowledge of COVID-19 as well as the rapid development of treatments. A broad-spectrum antiviral drug called Remdesivir has already shown antiviral efficacy against SARS-Cov-2 [68]. It was created by Gilead Sciences, which has produced treatments for the Ebola virus, according to other research [69]. The first case of COVID-19 reported in America was reportedly treated with Remdesivir [70]. According to one research, it was FDA-approved for clinical usage in people who had just been hospitalised [71]. Originally created as a potential therapy for influenza, molnupiravir is a broad range, immediately acting oral antiviral medication. Adults at risk who were unvaccinated and had mild-to-moderate laboratory-confirmed COVID-19 were treated early with molnupiravir to lower their risk of hospitalisation or death. In the early stages of the pandemic, lopinavir and ritonavir—an FDA-approved combination medicine for the treatment of HIV—was suggested as an antiviral treatment for covid-19. According to one research, lopinavir, a protease inhibitor, is used to treat HIV with ritonavir serving as a booster. In vitro experiments using the demonstrated anti-coronavirus activities [72]. For the treatment of COVID-19, the most often prescribed dosage of lopinavir/ritonavir was 400 mg/100 mg twice daily for up to 14 days. According to several research, lopinavir/ritonavir side effects might cause nausea, diarrhoea, and gastrointestinal discomfort [73]. Initially during the pandemic, chloroquine and hydroxychloroquine were suggested as antiviral therapies for covid-19 [74]. By preventing host receptor glycosylation, proteolytic processing, and endosomal acidification, they seem to prevent viral entrance into cells [75]. Chloroquine inhibits the replication of the novel coronavirus, according to one research [76]. With a half-maximal effective dose (EC50) in the low micromolar range, chloroquine suppresses SARS-CoV-2 in vitro. After 24 hours of development, hydroxychloroquine exhibits in vitro action with a lower EC50 for SARS-CoV-2 than chloroquine [77].

PREVENTION:

Till now there is no 100% efficient or reliable treatment present because the disease is not fully known or identified [78].Due to some nonspecific characters of disease I.e. infection occur before the appearance of symptoms in its incubation period, some people may have the disease and don’t show symptoms and therefore can transfer the disease to the healthy person accidentally due to absence of symptoms, the disease can be transferred even after the diseased person is clinically recovered. These are some reason which make the prevention a little difficult [79].

However, some pre-caution measure should be taken in order to have prevention from covid 19.

Following are some measures taken for prevention:

Isolation: The suspected and confirmed patient’s should be kept in isolation ward .isolation ward should be provided with all the basic facilities such as a private bathroom. It is important that all the necessities of the patient should be present in isolation area or isolation ward. The confirmed patients can be kept in same isolation room with 4 feet or 6 feet bed spacing [80]. The patients with mild illness can be isolated at home providing the proper ventilation and good sun light in order to destroy the virus [81]. Family should avoid visit to the patient’s room and can do electronic communication with the patient as prevention.

Use of mask: The patient, patient’s family members and healthcare personnel should wear mask in order to have prevention from the disease. There are two types of masks use as protective equipment against the disease.

MEDICAL /SURGICAL FACE MASK: It is estimated that this mask reduce the risk of disease transmission about 80%. When this mask is worn by health care worker it prevents the transmission of droplets. And when this mask is worn by the patient it will reduce the dispersal of virus containing droplets. Additionally when surgical mask is worn by patient it reduces the risk of contact transmission by reducing the contamination of nearby surfaces with the virus containing partials.

Usage rules for medical masks: Medical mask should not be touched. If you accidentally touched it then quickly wash your hands for 20 seconds with soap or use sanitizer. Medical mask should be used once. It should not be shared by two persons.

FILTERING FACEPIECE RESPIRATORS: By using polyethylene microfiber and electrostatic charge phenomenon this type of mask achieve filtration. These are high-performance filtering mask for example N95 or FFP2. These masks should be fit tested and seal should be checked by the user before entering the contaminated area. These masks should be used by HCW if they are providing direct care where aerosol-generating procedures such as suction or intubation are frequently taking place. In early times of Covid-19 pandemic which type of mask should be used was a matter of debate. Many physicians suggests that all those personnel should wear N95 or equivalent masks who are responsible for the care of Covid-19 patients ,however studies comparing the effect of N95 respirator and surgical mask among the health care workers have conflicting results because these studies have some faults. As these mask give more efficient filtration as compared to surgical mask the health care workers should use N95 respirators because HCW are at high risk of transmission as it is evident from the fact that till date 1500 HCW in China are infected by Covid-19 causing death of 6 HCW including the doctor who first warned about the disease.

Disinfection of isolation wards: The isolation ward should be disinfected. The visible or larger pollutants shall be first removed from the floor, walls object surface .After that they should be disinfected 1000g/l chlorine containing disinfectant through spraying or mopping. The procedure of disinfection should be carried out for 30 minutes and three time a day.

Air disinfection: Plasma air sterilisers should be used for air disinfection. If plasma air sterilisers are not present ultraviolet lamps can be used for one hour to achieve air disinfection in the areas with human activity. This process should be reformed at least three times a day.

HOSPITAL PRACTICE PROTOCOLS: Following protocol should be followed by doctors /HCW while dealing with the Covid-19 patients.

Wear special work clothes and work shoes; then wash hands properly; wear disposable surgical cap; Put on protective mask I.e. N95; Wear inner disposable latex gloves; Put on Google and protective clothing; Wear outer disposal latex gloves; Donning completed to deal with covid-19 patients [82].

PREVENTIONAL MEASURES AT COMMUNITY LEVEL:

At community level, people should follow the given measures [83]:

Avoid crowded areas: People should avoid crowded area such as parks, shopping mall wedding halls and other social gatherings.

Six feet distance: People should maintain up to 6 feet distance between them in markets or stores etc.

Cough hygiene: They should follow cough hygiene I.e instead of coughing in hand they should cough in sleeves or tissue.

Hand hygiene: People should follow hand hygiene I.e. wash the hands every 15-20 minutes. Use of hand sanitizer should also be facilitated.

Use of mask: Those people with respiratory symptoms must wear surgical masks [84, 85]. In China the public has been asked to wear masks in public and crowded areas [86].

Travel restrictions: During the start of pandemic travel restrictions were imposed on China. People who were returning from China were first checked for the symptoms and tested of Covid-19.they were quarantined for 2 weeks even if they doesn’t show any symptoms. Due to the rapid spread of Covid-19 the travel restrictions has been extended to many other countries where ratio of disease is high [87].

These are some efforts which will help to slow down the spread of this viral disease up to some extent.

Conclusion:

The outbreak of corona virus is the deadliest in modern eras. The substantial and solid stances taken for the diagnosis of SAR-CoV 2 variant to cause COVID 19 pandemic was a major development. The sign symptoms of breath shortness and majorly low oxygen made it quite significant and clear to get to the revelation of a disease different from pneumonia. The diagnostic steps by the scientific and research community were tiring and challenging task, leading to its treatment and vaccination accompanied by boosters that are still administered to hype the immunity. After all the safety measures and precautions of using sanitizers, distance speech, masks and few others are the crucial of all that will lead to almost none chances of getting infecting. Keep safe and stay healthy.

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https://link.springer.com/article/10.1007/s12098-020-03263-6

Literature review on covid-19 pandemic