Coronavirus (COVID-19) Collection
- From the end of 2020, multiple variants of concern have emerged during the COVID-19 pandemic. Most recently, the Omicron variant has become dominant worldwide over other strains, with the potential for the emergence of other new variants or subvariants in the future. The Omicron variants have demonstrated increasing transmissibility and therefore are more challenging to control (Kraemer et al., 2021; World Health Organization, 2022). In general, increased transmissibility for a variant indicates an increased transmission strength, a higher transmission speed, or both.
- The transmission routes of SARS-CoV-2, the pathogen of COVID-19, remain still partly unclear (Yang and Duan G, 2020). According to present knowledge (Chinese Thoracic Society and Chinese Association of Chest Physicians, 2021), the main transmission routes of COVID-19 are respiratory droplets from close contacts and aerosols in confined spaces (Rabaan et al., 2021; Schijven et al., 2021). However, there is no evidence to exclude the possibility of other routes of transmission, such as gastrointestinal tract transmission (Jiao et al., 2021).
- COVID-19, a new contagious respiratory disease, occurred at the end of 2019, in Wuhan, China (Zu et al., 2020), and spread globally rapidly. Although various endeavors have been taken, the disease has not been well controlled except in a few countries. Up to now, COVID-19 has led to over millions of deaths, and become a pandemic and global public health crisis. The pathogen of COVID-19 was quickly confirmed to be SARS-CoV-2 (Schijns et al., 2020).
- On 31 December 2020, China first reported a group of cases with atypical pneumonia caused by the SARS-CoV-2 (Lu et al., 2020). As of 8 December 2020, more than 68.5 million people were infected with the virus, and >1.5 million have died as a result of it (World Health Organization, 2020). In Spain, to date, >1.5 million people have been diagnosed with COVID-19 infection, and 47 624 people have died from the disease (Spanish Government, 2020). To reduce the risk of transmission, governments have launched urgent measures that include widespread use of facemasks, closure of public spaces and personal mobility restrictions.
- SARS-CoV-2, the virus causing Coronavirus disease 2019 (COVID-19), has infected more than 92 million people and lead to the death of more than 1.9 million people worldwide since its outbreak in December 2019 (WHO, 2020). The disease has a wide range of presentations, from asymptomatic infection to fever, cough, shortness of breath and the loss of taste and smell. Symptoms normally appear 2–14 days following exposure to the virus and may develop into mild upper respiratory tract infections or progress to severe pneumonia, which can progress to acute respiratory distress, shock, multiorgan failure and death (Huang et al., 2020; Wang et al., 2020).
- The outbreak of novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-induced disease, COVID-19, spread rapidly from Wuhan, China, in December 2019. This led to China experiencing a major public health emergency with over 83,000 confirmed cases and 4634 deaths as of June 2020 (Rai et al., 2020). Although there are a few newly developed vaccines and treatments, it is conceivable that without some impact on transmission, the virus will continue to circulate, infect, and cause serious disease, in certain segments of the unvaccinated population.
- A combination of physical distancing measures, if implemented early, can be effective in containing COVID-19—tight border controls to limit importation of cases, encouraging physical distancing, moderately stringent measures such as working from home, and a full lockdown in the case of a probable uncontrolled outbreak.
- A novel coronavirus (SARS-CoV-2) originating from Wuhan spread rapidly around the world to give rise to the most important pandemic event in recent history. As of May 17, 2020, the cumulative number of confirmed cases had reached 3.5 million, including 250,000 deaths (WHO, 2019). Early mean estimates of the reproduction number, based on the epidemic's growth rate, were estimated to be in the range of 1.4–3.5, comparable with estimates for seasonal flu, the 2009 pandemic flu, SARS, and MERS (WHO, 2005; Biggerstaff et al., 2014; Chowell et al., 2004; Chowell et al., 2014; Kucharski et al., 2020; Liu et al., 2020).