August 2017: Recommendation 18.104.22.168. was added to cross-refer to the NICE guideline on sepsis: recognition, diagnosis and early management. Recommendation 22.214.171.124 was added to highlight that clinicians should not use a response to antipyretic therapy alone as a means to differentiate between serious and non-serious infection. A footnote was added to recommendation 126.96.36.199 and Table 1 to highlight that some vaccinations have been found to induce fever in children younger than 3 months.
This guideline updates and replaces NICE clinical guideline 47 (published May 2007).
Recommendations are marked as , [2007, amended 2013],  or [new 2013]:
Some recommendations can be made with more certainty than others. The Guideline Development Group makes a recommendation based on the trade-off between the benefits and harms of an intervention, taking into account the quality of the underpinning evidence. For some interventions, the Guideline Development Group is confident that, given the information it has looked at, most patients would choose the intervention. The wording used in the recommendations in this guideline denotes the certainty with which the recommendation is made (the strength of the recommendation).
For all recommendations, NICE expects that there is discussion with the patient about the risks and benefits of the interventions, and their values and preferences. This discussion aims to help them to reach a fully informed decision (see also patient-centred care).
We usually use 'must' or 'must not' only if there is a legal duty to apply the recommendation. Occasionally we use 'must' (or 'must not') if the consequences of not following the recommendation could be extremely serious or potentially life threatening.
We use 'offer' (and similar words such as 'refer' or 'advise') when we are confident that, for the vast majority of patients, an intervention will do more good than harm, and be cost effective. We use similar forms of words (for example, 'Do not offer…') when we are confident that an intervention will not be of benefit for most patients.
We use 'consider' when we are confident that an intervention will do more good than harm for most patients, and be cost effective, but other options may be similarly cost effective. The choice of intervention, and whether or not to have the intervention at all, is more likely to depend on the patient's values and preferences than for a strong recommendation, and so the healthcare professional should spend more time considering and discussing the options with the patient.
NICE began using this approach to denote the strength of recommendations in guidelines that started development after publication of the 2009 version of 'The guidelines manual' (January 2009). This does not apply to any recommendations ending  (see 'Update information' above for details about how recommendations are labelled). In particular, for recommendations labelled  the word 'consider' may not necessarily be used to denote the strength of the recommendation.