Table 2.

Emerging respiratory viruses – key symptoms, signs, investigations and management1, 2, 3, 4

Virus	Symptoms	Signs	Investigations	Management
Seasonal influenza	•Incubation period 2 days •Myalgia, lethargy, headache •Dry cough that can last for 2 or more weeks •Sore throat, rhinorrhoea •Diarrhoea, abdominal pain, nausea, vomiting	•Fever >38°C	•Diagnosis based on signs and symptoms •Nasopharyngeal and throat swabs	•Seasonal influenza vaccination, especially for high-risk groups •Most recover without needing medical attention •Encourage fluid intake •Neuraminidase inhibitors,a follow guidance •Resistance to adamantanes
H1N1	•Incubation period 2–7 days •Usual seasonal flu symptoms •Complications: shortness of breath, bloody sputum, chest pain, drowsiness, confusion, dehydration	•Initially fever >38°C	•Diagnosis based on signs and symptoms •Nasopharyngeal and throat swabs	•Monovalent pandemic vaccine available •2017–2018 seasonal flu vaccine contains H1N1 •Neuraminidase inhibitors,a follow guidance
A(H5N1)	•Incubation period 2–5 days, ranging to 17 days •Contact history with birds •History of travel •Cough •Malaise and myalgia •Occasionally abdominal and chest pain, diarrhoea and vomiting •Some patients have bleeding nose and gums •Can progress quickly to shortness of breath, acute respiratory distress syndrome, with altered mental state and seizures •Sore throat and coryza less common	•Fever >38°C •Hypoxaemia •Multiple organ dysfunction •Secondary bacterial and fungal infection •60% mortality	•Nasopharyngeal and throat swabs are the most sensitive •Chest X-ray consolidation or acute respiratory distress syndrome	•There is some evidence to support that oseltamivir reduces severity and prevents death •Follow treatment guidance •Corticosteroids not recommended unless adrenal insufficiency •Vaccines developed but not available for widespread use. WHO does not have a stockpile
A(H7N9)	•Incubation period 1–10 days, average 5 days •Contact history with birds/poultry •History of travel •Cough •Shortness of breath •Occasionally diarrhoea, vomiting, abdominal and chest pain •Some patients have bleeding nose and gums •Sore throat and coryza less common	•Fever >38°C •Hypoxaemia •Multiple organ dysfunction •Secondary bacterial and fungal infection •40% mortality •Rapidly progressing severe pneumonia	•Nasopharyngeal and throat swabs are the most sensitive	•There is some evidence to support that oseltamivir reduces severity and prevents death but reduced efficacy shown •Resistance shown to adamantanes •Corticosteroids not recommended unless adrenal insufficiency •Vaccines in efficacy and safety trials
SARS-CoV	•Incubation period 2–10 days •Headache and myalgia •Shortness of breath •Up to 70% have diarrhoea •After 2–7 days, dry cough develops with pneumonia •Rhinorrhoea, sore throat and chest pain are uncommon •Travel to China, Hong Kong or Taiwan •Contact with SARS-CoV via healthcare work or research	•Initially fever >38°C •Hypoxia •10% case fatality, 50% in >60 years old •Children less severely affected •Lack of respiratory signs, especially in elderly patients	•Chest X-ray showing pneumonia by day 7–10 of illness (patchy consolidation developing into ground-glass appearance, pneumothorax possible) •Lymphopenia in most cases •Often raised LDH •Nasopharyngeal and throat swabs or aspirate are most sensitive •Sputum, blood, urine and stool samples also possible	•No vaccine •Discuss with experts regarding potential therapies in addition to supportive care. Ideally, these should be studied in the framework of a clinical trial. •Personal protection equipment
MERS-CoV	•Commonly: cough, shortness of breath, fever •Occasionally diarrhoea •Some patients develop severe acute respiratory disease, multiorgan failure and septic shock •Some patients are asymptomatic (often found on contact tracing) •Contact with dromedary camels or consumption of undercooked meat or milk •Travel to a high-risk country or contact with a possible case 14 days before onset of illness •Rarely seen in children	•Fever >38°C •35% mortality	•Pneumonia may or may not be present, including on chest X-ray •Sputum, aspirate or bronchiolar lavage samples are more sensitive •Nasopharyngeal and throat swabs if above not possible •Broncheolar lavage, EDTA blood, urine, stool and serum tests may be required after initial positive result •Raised LDH/creatinine/liver function, leucopenia, lymphopenia, thrombocytopenia	•No vaccine or treatment available •Supportive management •MERS-CoV antibodies, interferon and lopinavir are possibilities – PHE will advise •Corticosteroids are contraindicated •Isolation of close contacts for 14 days, with daily monitoring and laboratory testing for high-risk contacts

LDH, lactate dehydrogenase.

^aOseltamivir (Tamiflu^®) and zanamivir (Relenza^®) in the UK. In certain countries, other neuraminidase inhibitors are licensed. Peramivir (Rapivab^®) and laninamivir are recommended by the WHO in addition to oseltamivir and zanamivir. Peramivir is in development in the UK and recommendations will be published by NICE in September 2018.¹