Wuhan coronavirus: Infected people may not show any symptom of disease and might not know of their infection
People infected with Wuhan Coronavirus may not even know they are carrying the disease since there might be no visible symptoms. This, according to a study on a whole family, where six members were infected, but one child with the virus did not show any symptoms.
The family traveled to Wuhan from Shenzhen between December 29, 2019, and January 4, 2020.
Of the six family members, five were identified as infected with the novel coronavirus. Additionally, one family member, who did not travel to Wuhan, got infected with the virus after several days of contact with four of the family members. None of the family members had contacts with Wuhan markets or animals, although two had visited a Wuhan hospital.
On January 10, 2020, medical experts enrolled two patients who initially presented to The University of Hong Kong Shenzhen Hospital (Shenzhen, Guangdong province, China) with fever, respiratory symptoms, and pulmonary infiltrates on chest radiographs. Subsequently, between January 11, and January 15, 2020, remaining members of the family also came to the hospital for the assessment of their health conditions.
The 10-year-old child, referred to as 'patient 5' in the study, was later confirmed virologically to have an asymptomatic infection. Patients 1–4 were symptomatic, and they came to the hospital 6–10 days after symptom onset.
“Five family members (aged 36–66 years) presented with fever, upper or lower respiratory tract symptoms, or diarrhea, or a combination of these 3–6 days after exposure. They presented to our hospital (The University of Hong Kong-Shenzhen Hospital, Shenzhen) 6–10 days after symptom onset. They and one asymptomatic child (aged 10 years) had radiological ground-glass lung opacities,” say the researchers in their findings published in The Lancet.
It is one of the first reports of clinical data from initial cases of the 2019 novel coronavirus (2019-nCoV).
“For the two asymptomatic children (patients 5 and 6), patient 5 had ground-glass lung opacities identified by CT scan. Unlike patient 5, who was aged 10 years and non-compliant to parental guidance, patient 6, who was aged 7 years and reported by her mother to wear a surgical mask for most of the time during the period in Wuhan, was not found to be infected by virological or radiological investigations,” says the study.
According to the researchers, the analysis reveals that person-to-person transmission in family homes or hospital and intercity spread of this novel coronavirus are possible, and therefore “vigilant control measures are warranted at this early stage of the epidemic.” They recommend isolating patients as soon as possible.
“As shown in this study, it is still crucial to isolate patients and trace and quarantine contacts as early as possible because asymptomatic infection appears possible (as shown in one of our patients), educate the public on both food and personal hygiene, and alert health-care workers on compliance to infection control to prevent superspreading events,” says the team.
Less than half had underlying diseases
In a second report, also published in The Lancet, the researchers analyzed 41 admitted hospital patients (including the Shenzhen family) who had been identified as having laboratory-confirmed 2019-nCoV infection. The data shows 20 (49%) of the 2019-nCoV-infected patients were aged 25–49 years and 14 (34%) were aged 50–64 years. The median age of the patients was 49 years.
According to the analysis, less than half of the infected patients had underlying diseases (13 or 32%), including diabetes (eight [20%]), hypertension (six [15%]), and cardiovascular disease (six [15%]). This shows that healthy people with no underlying health conditions can be infected with Wuhan Coronavirus.
Patients had serious, sometimes fatal, pneumonia and were admitted to the designated hospital in Wuhan, China, by January 2, 2020. According to the analysis, patients infected with 2019-nCoV might develop acute respiratory distress syndrome (ARDS), have a high likelihood of admission to intensive care, and might die.
“Most of the infected patients were men (30 or 73%); less than half had underlying diseases. 27 (66%) patients had direct exposure to Huanan seafood market,” says the team.
The study also shows that 2019-nCoV caused clusters of fatal pneumonia with clinical presentation greatly resembling SARS-CoV.
“In this cohort, most patients presented with fever, dry cough, dyspnoea, and bilateral ground-glass opacities on chest CT scans. These features of 2019-nCoV infection bear some resemblance to SARS-CoV and MERS-CoV infections,” the findings state.
Patients with severe illness developed ARDS and required ICU admission and oxygen therapy. The time between hospital admission and acute respiratory distress syndrome and shock was as short as two days. “At this stage, the mortality rate is high for 2019-nCoV because six (15%) of 41 patients in this cohort died,” say experts.
The researchers describe that the first fatal case, who had continuous exposure to the market, was admitted to hospital because of a 7-day history of fever, cough, and dyspnoea. Five days after illness onset, his wife, a 53-year-old woman who had no known history of exposure to the market, also presented with pneumonia and was hospitalized in the isolation ward.
Overall, the most common symptoms at the onset of illness were fever (40 or 98% of 41 patients), cough (31 or 76%), and myalgia or fatigue (18 or 44%). “Less common symptoms were sputum production (11 [28%] of 39), headache (three [8%] of 38), hemoptysis (two [5%] of 39), and diarrhea (one [3%] of 38; table 1). More than half of the patients (22 [55%] of 40) developed dyspnoea. The median duration from illness onset to dyspnoea was 8.0 days,” says the study.
The researchers say that taken together, the evidence so far indicates human transmission for 2019-nCoV. “We are concerned that 2019-nCoV could have acquired the ability for efficient human transmission,” says the team.
According to a comment published in The Lancet, the picture these two studies paint is of a disease with a 3–6 day incubation period and insidious onset.
“The information in these articles are pieces of the jigsaw puzzle that are being fit together by WHO as it continues to collect official reports and informal information from its virtual groups of national clinicians, epidemiologists, and virologists working at outbreak sites and brought together from around the world. When pieced together, these emerging data will permit regular refinement of the risk assessment, and real-time guidance to countries for patient management and outbreak control, including the best case definition for use in surveillance around outbreak sites and elsewhere,” says David L Heymann from Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, UK.