Do not offer an antibiotic for preventing or treating pneumonia if SARS-CoV-2, another virus, or a fungal infection, is likely to be the cause.
Antibiotics do not work on viruses, and inappropriate antibiotic use may reduce availability. Also, inappropriate use may lead to Clostridioides difficile infection and antimicrobial resistance, particularly with broad-spectrum antibiotics. [23 March 2021]
Evidence as of March 2021 suggests that bacterial co-infection occurs in less than about 8% of people with COVID-19, and could be as low as 0.1% in people in hospital with COVID-19. Viral and fungal co-infections occur at lower rates than bacterial co-infections.
Secondary infection or co-infection (bacterial, viral or fungal) is more likely the longer a person is in hospital and the more they are immunosuppressed (for example, because of certain types of treatment).
The type and number of secondary infections or co-infections will vary depending on the season and any restrictions in place (for example, lockdowns).
To help identify other causes of pneumonia and to inform decision making about using antibiotics, consider the following tests:
a full blood count
chest imaging (X-ray, CT or ultrasound)
respiratory and blood samples (for example, sputum or a tracheal aspirate sample, blood culture)
urine samples for legionella and pneumococcal antigen testing
throat, nasopharyngeal or sputum samples for respiratory viral (and atypical pathogen) polymerase chain reaction testing; for more information, see Public Health England's COVID-19 guidance for sampling and for diagnostic laboratories. [23 March 2021, amended 27 July 2022]
High C-reactive protein levels do not necessarily indicate whether pneumonia is due to bacteria or SARS‑COV‑2.
Low C-reactive protein level indicates that a secondary bacterial infection is less likely.
Do not use C-reactive protein to assess whether a person has a secondary bacterial infection if they have been having immunosuppressant treatment. [23 March 2021]
There is insufficient evidence to recommend routine procalcitonin testing to guide decisions about antibiotics. Centres already using procalcitonin tests are encouraged to participate in research and data collection.
Procalcitonin tests could be useful in identifying whether there is a bacterial infection. However, it is not clear whether they add benefit beyond what is suggested in recommendation 6.2.1 on tests to help differentiate between viral and bacterial pneumonia to guide decisions about antibiotics. The most appropriate threshold for procalcitonin is also uncertain.
Do not offer an antibiotic for preventing secondary bacterial pneumonia in people with COVID-19. [23 March 2021]
If a person has suspected or confirmed secondary bacterial pneumonia, start antibiotic treatment as soon as possible. Take into account any different methods needed to deliver medicines during the COVID-19 pandemic (see recommendation 3.1.1 on minimising face-to-face contact).[23 March 2021]
For antibiotic choices to treat community-acquired pneumonia caused by a secondary bacterial infection, see the recommendations on choice of antibiotic in NICE's guideline on pneumonia (community-acquired): antimicrobial prescribing.
Advise people to seek medical help without delay if their symptoms do not improve as expected, or worsen rapidly or significantly, whether they are taking an antibiotic or not. [23 March 2021]
On reassessment, reconsider whether the person has signs and symptoms of more severe illness (see recommendation 2.1.1 on signs and symptoms to help identify people with COVID-19 with the most severe illness) and whether to refer them to hospital, other acute community support services or palliative care services. [23 March 2021]
Start empirical antibiotics if there is clinical suspicion of a secondary bacterial infection in people with COVID-19. When a decision to start antibiotics has been made:
Start empirical antibiotic treatment as soon as possible after establishing a diagnosis of secondary bacterial pneumonia, and certainly within 4 hours.
If the person has suspected sepsis, start treatment in line with NICE's guidelines on suspected sepsis in under 16s, people aged 16 or over and people who are or have recently been pregnant. [23 March 2021]
To guide decision making about antibiotics for secondary bacterial pneumonia in people with COVID-19, see NICE's guideline on pneumonia (hospital-acquired): antimicrobial prescribing.
When choosing antibiotics, take account of:
local antimicrobial resistance data and
other factors such as their availability. [23 March 2021]
Give oral antibiotics if the person can take oral medicines and their condition is not severe enough to need intravenous antibiotics. [23 March 2021]
Consider seeking specialist advice on antibiotic treatment for people who:
are immunocompromised
have a history of infection with resistant organisms
have a history of repeated infective exacerbations of lung disease
are pregnant
are receiving advanced respiratory support or organ support. [23 March 2021]
Seek specialist advice if:
there is a suspicion that the person has an infection with multidrug-resistant bacteria and may need a different antibiotic or
there is clinical or microbiological evidence of infection and the person's condition does not improve as expected after 48 to 72 hours of antibiotic treatment. [23 March 2021]
Review all antibiotics at 24 to 48 hours, or as soon as test results are available. If appropriate, switch to a narrower-spectrum antibiotic, based on microbiological results. [23 March 2021]
For intravenous antibiotics, review within 48 hours and think about switching to oral antibiotics (in line with NICE's guideline on pneumonia [hospital-acquired]: antimicrobial prescribing)
Give antibiotics for 5 days, and then stop them unless there is a clear indication to continue (see recommendation 6.2.12 on when t