In late 2019 a new respiratory illness appeared in Wuhan, China caused by SARS-CoV-2, a betacoronavirus similar to SARS and MERS, both of which originated in bats. The respiratory illness, coronavirus disease-19 (COVID-19) expanded rapidly and now represents an evolving public health emergency with new information published daily. Some of the information presented here may later be shown to be incorrect as our understanding of COVID-19 expands. Facebook, Twitter, and other social media sites are NOT reliable sources of information. Please use the resources listed on the opening page of this website to stay updated during the current COVID-19 outbreak.
What is COVID-19?
SARS-CoV-2 belongs to family of viruses that cause a broad range of symptoms, ranging from the common cold to more severe infections. These viruses are large, enveloped, positive-sense single-stranded RNA viruses.1 Previous coronavirus outbreaks causing severe disease include severe acute respiratory syndrome (SARS-CoV; 2002–2003) and the Middle Eastern respiratory syndrome coronavirus (MERS-CoV; 2012–present).
Coronaviruses that cause the common cold are commonplace and widespread, accounting for 10% to 30% of upper respiratory tract infections in adults. The incidence of these infections increases during the winter months. Laboratory tests that detect these pervasive coronaviruses are not able to detect SARS-CoV-2.1
Where and when was COVID-19 first detected?
On December 30, 2019, a cluster of pneumonia cases of unknown etiology in Wuhan, China was reported to Chinese public health authorities. Most cases reported an exposure to the Wuhan seafood market, which was closed on January 1, 2020.2 A novel coronavirus was first reported on January 7, and the first fatal case occurred on January 11. The first case outside of China was reported in Thailand on January 13,3 and the first U.S. case was reported on January 20.3 Initially, all cases reported outside of China were in returning travelers from Wuhan province.2
Which countries/regions are affected by the current outbreak?
WHO: Reported Cases of COVID-19 as of July 8 (by WHO Region)
Total (new cases in last 24 hours)
|Globally||11,669,259 (168,957)||539,906 (4,147)|
|Africa||397,942 (15,379)||7,415 (276)|
|Americas||6,004,685 (89,134)||268,828 (2,092)|
|Eastern Mediterranean||1,204,698 (17,078)||28,664 (562)|
|Europe||2,827,789 (17,941)||201,255 (604)|
|South-East Asia||1,001,655 (27,266)||26,224 (605)|
|Western Pacific||231,749 (2,159)||7,507 (8)|
The United States has assisted with voluntary evacuations of U.S. citizens from China, and the U.S. Centers for Disease Control and Prevention (CDC) has issued travel risk assessments.
How many cases of COVID-19 are there? How many patients have died?
As of July 8, there were 11,669,259 confirmed cases of COVID-19 with 539,906 deaths reported.4 The case fatality rate (CFR) is estimated to be between 0.6% (South Korea) and 5.0% (Italy).4 There are several caveats that make it difficult to determine what the most accurate CFR is at this time. On the one hand, many of the recently reported cases remain sick, with some in critical care, so there is a lag between reporting of cases and clinical outcome, which could increase the CFR. On the other hand, case detection has focused on patients with clinically significant and severe illness, so patients with mild symptoms or without symptoms may not be recognized which could result in a higher computed CFR. In general, countries with aggressive case-finding measures (such as South Korea) report a CFR that is lower than that for countries with more limited testing capacity (including the US as of March 9th).
The total number of cases is higher than occurred in the SARS-CoV and MERS-CoV outbreaks.5 The case fatality rate (CFR) and percentage of patients with severe disease are both lower than reported for SARS-CoV and MERS-CoV. For comparison, 774/8098 (9.6%) of patients with SARS-CoV died, and 858/2494 (34.4%) of patients with MERS-CoV died.5
Texas and Harris County COVID-19 cases
Texas COVID-19 Reported Cases – July 8
Total state-wide cases: 220,564 ; Deaths: 2,813
|County of Residenceb||Casesc||Deaths|
- DSHS will update the state case count each day by noon Central Time.
- Patient may be undergoing treatment in facilities in other counties
- Does not include repatriation cases.
The Centers for Disease Control and Prevention (CDC) has confirmed multiple cases of novel coronavirus 2019 in people under federal quarantine at the Joint Base San Antonio-Lackland. The first was a traveler who returned on a U.S. State Department-chartered flight from Wuhan City, China. The others returned on a State Department flight for passengers from the Diamond Princess cruise ship quarantined in Yokohama, Japan. Most of the travelers have completed their quarantine period and returned home. Some individuals who tested positive will remain isolated until they test negative for the virus and are no longer at risk of spreading it. The CDC has the latest information on the number of people under quarantine who are infected and is updating its national numbers each Monday, Wednesday, and Friday. Those cases are not included in the Texas case count.
How does COVID-19 spread?
Person-to-person transmission is likely the most common means of transmission.6,7 Based on how other coronaviruses spread, droplet transmission is presumed. Recent articles have found evidence that the virus can be detected in stool, suggesting that contact precautions and good handwashing are warranted.8,9 It remains unknown if fomites can transmit the virus.
Case reports suggest that the virus can be transmitted by patients who are asymptomatic or who have mild symptoms.
Transmission to healthcare workers was a key feature of the SARS-CoV epidemic during 2002–2003. A case series of 138 hospitalized patients with COVID-19 in Wuhan found that hospital-associated transmission was suspected as the presumed mechanism of transmission in 40 (29%) affected health professionals and in 17 (12.3%) affected patients.10
One measure of a pathogen’s ability to spread is the basic reproductive number, also known as R0 (R-naught). This number is an estimate of the average number of people to whom one person infected with the pathogen transmits the disease. For example, an R0 of 2.0 means that each person with the disease infects two new people.
The R0 for COVID-19 has been estimated at 2.2–3.6 in one study11 and 2.2 in another.7 A recent metanalysis found that the median R0 from modeling studies was 2.8, with an interquartile range of 1.6-4.0.12 As we continue to identify cases and our understanding of this virus expands, this number may change. This estimate is higher than the R0 value for MERS-CoV (<1.0)6 and is similar to the R0 value for SARS-CoV (2.0–5.0).6 For comparison, the R0 for pandemic influenza (2009 H1N1) was estimated to be 1.2–2.3.13
An important epidemiologic phenomenon during the SARS-CoV outbreak was “superspreaders” — individuals with the disease who infected a much larger number of people than the R0 for SARS-CoV. It is unknown if this phenomenon will similarly affect the transmission dynamics of COVID-19.
- Paules CI, Marston HD, Fauci AS. Coronavirus Infections—More Than Just the Common Cold. JAMA. 2020;37(October):435. doi:10.1001/jama.2020.0757
- Wang C, Horby PW, Hayden FG, Gao GF. A novel coronavirus outbreak of global health concern. Lancet. 2020;6736(20):1-4. doi:10.1016/S0140-6736(20)30185-9
- Holshue ML, DeBolt C, Lindquist S, et al. First Case of 2019 Novel Coronavirus in the United States. N Engl J Med. January 2020:NEJMoa2001191. doi:10.1056/NEJMoa2001191
- WHO. Coronavirus disease 2019. World Heal Organ. 2020;2019(March):2633. doi:10.1001/jama.2020.2633
- Mahase E. China coronavirus: what do we know so far? BMJ. 2020;368(January):m308. doi:10.1136/bmj.m308
- Fuk-Woo Chan J, Yuan S, Kok K-H, et al. A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster. Lancet. 2020;6736(20):1-10. doi:10.1016/S0140-6736(20)30154-9
- Li Q, Guan X, Wu P, et al. Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus-Infected Pneumonia. N Engl J Med. 2020:1-9. doi:10.1056/NEJMoa2001316
- Gu J, Han B, Wang J. COVID-19: Gastrointestinal manifestations and potential fecal-oral transmission. Gastroenterology. 2020. doi:10.1053/j.gastro.2020.02.054
- Xiao F, Tang M, Zheng X, et al. Evidence for gastrointestinal infection of SARS-CoV-2. medRxiv. 2020:2020.02.17.20023721. doi:10.1101/2020.02.17.20023721
- 10Wang D, Hu B, Hu C, et al. Clinical Characteristics of 138 Hospitalized Patients with 2019 Novel Coronavirus-Infected Pneumonia in Wuhan, China. JAMA - J Am Med Assoc. 2020:1-9. doi:10.1001/jama.2020.1585
- Zhao S, Lin Q, Ran J, et al. Preliminary estimation of the basic reproduction number of novel coronavirus (2019-nCoV) in China, from 2019 to 2020: A data-driven analysis in the early phase of the outbreak. Int J Infect Dis. 2020;243:153057. doi:10.1016/j.ijid.2020.01.050
- Liu Y, Gayle AA, Wilder-Smith A, Rocklöv J. The reproductive number of COVID-19 is higher compared to SARS coronavirus. J Travel Med. 2020;(Figure 1):1-4. doi:10.1093/jtm/taaa021
- Boëlle PY, Ansart S, Cori A, Valleron AJ. Transmission parameters of the A/H1N1 (2009) influenza virus pandemic: A review. Influenza Other Respi Viruses. 2011;5(5):306-316. doi:10.1111/j.1750-2659.2011.00234.x