WHO AWaRe (Access, Watch, Reserve) classification of antibiotics
- Classifies antibiotics into three groups – Access, Watch and Reserve – based on the potential to cause resistance.
- Identifies antibiotics that are priorities for monitoring and surveillance of use
- Also defines a group of "Not recommended" antibiotics, whose use is not recommended nor supported by evidence.
The clock is ticking
Most medicines remain effective even if used by many people for prolonged periods. Unfortunately, antibiotics are an important exception as they can become ineffective because of antibiotic resistance.
Infections caused by bacteria that are resistant to antibiotics are more difficult to treat and are responsible for a high number of deaths worldwide.
Anti-microbal resistance
Antimicrobial resistance (AMR) occurs when bacteria, viruses, fungi and parasites change over time and no longer respond to medicines. This makes infections harder to treat and increases the risk of disease spread, severe illness and death.
Antibiotic resistance refers to the ability of bacteria to withstand the effects of an antibiotic.
When bacteria develop resistance, they are no longer inhibited or killed by a given antibiotic. Antibiotic resistance occurs naturally over time, usually through genetic changes.
Around half of antibiotic use in humans is inappropriate (not clinically indicated).
Inappropriate use of antibiotics leads to more rapid emergence and spread of antibiotic resistance, amplifying the natural ability of bacteria to resist the effects of antibiotics.
The most common inappropriate use of antibiotics is in primary health care, for treatment of mild respiratory tract infections, that are most commonly caused by viruses.
Antibiotic vs. Bacteria
Antibiotics are vital to treat severe bacterial infections, but bacteria are developing new strategies to counter the effect of antibiotics. Some bacteria that cause infections in humans are becoming increasingly resistant to key antibiotics, limiting treatment options for severe infections.
Important
In order to keep antibiotics effective, we need to take them only when needed and strictly as directed by the prescriber / healthcare professional
Furthermore, there is a need to select the right antibiotic for a given infection when they are needed. Those antibiotics that offer the best therapeutic advantage while minimizing the risk of resistance should be privileged.
WHO
Classification of antibiotics
To address these issues, WHO developed the AWaRe classification of antibiotics – a framework based on three different categories – Access, Watch and Reserve.
access
group
- Access group antibiotics are generally “narrow spectrum” and have activity against a wide range of common bacteria, while also having generally lower resistance potential than antibiotic in the other groups.
- Selected Access group antibiotics are recommended as essential first- or second-choice empiric treatment options for specified infectious syndromes in the WHO Model Lists of Essential Medicines.
- Access group antibiotics have generally low levels of toxicity with a well-established safety profile.
- Nearly all oral antibiotics in the primary care setting should be Access group antibiotics.
watch
group
- Watch group antibiotics are more “broad spectrum” and generally have a higher resistance potential than Access group antibiotics.
- Watch group antibiotics should be prioritized as key targets of stewardship programmes and monitoring because they are at relatively high risk of selection of bacterial resistance.
- Their use should be limited to infections where they provide clear benefits over antibiotics in the Access group and should be avoided for other infections.
- Selected Watch group antibiotics are recommended as essential first- or second-choice empiric treatment options for a limited number of specific infections in the WHO Model Lists of Essential Medicines.
- Watch group antibiotics generally have higher levels of toxicity than Access group antibiotics.
- Watch group antibiotics are used mostly in the hospital setting and are administered by injection. There are only a few indications for oral Watch group antibiotics.
reserve
group
- Reserve group antibiotics should be reserved for the treatment of patients with confirmed or suspected serious (e.g. life-threatening) infections caused by bacteria that are resistant to a large number of Access and Watch group antibiotics.
- Reserve group antibiotics must be closely monitored and prioritized as targets of stewardship programmes to ensure their continued effectiveness.
- Reserve group antibiotics should be available, but their use should be strictly limited to highly specific patients and settings, when all alternatives have failed, or are not suitable.
- Selected Reserve group antibiotics are essential treatment options for multidrug-resistant bacteria and are included in the WHO Model Lists of Essential Medicines.
All groups: sufficient supplies should exist worldwide
NOT RECOMMENDED GROUP
- This group includes antibiotics whose use is not supported by evidence, nor recommended in high quality international guidelines.
- This group includes mainly fixed-dose combinations of multiple antibiotics.
- These antibiotics are not included on the WHO Model Lists of Essential Medicines and their use in clinical practice is not recommended.
How were the AWaRe antibiotic groups created?
In 2017 WHO reviewed 21 common infections, and, balancing benefits, harms and the potential for resistance, selected the most appropriate first and second-choice empiric antibiotic treatment options for each infection for inclusion on the Model Lists of Essential Medicines. Taking into consideration the need for effective antimicrobial stewardship, as well as the need to ensure access to essential antibiotics and appropriate prescribing, these essential antibiotics were classified into the three groups: Access, Watch and Reserve.
In 2019, the AWaRe classification was expanded beyond the WHO Model Lists of Essential Medicines, to include commonly used antibiotics globally.
Since then, the AWaRe classification has been reviewed and updated by WHO every 2 years.
WHO has also published the AWaRe antibiotic book which provides detailed guidance on the choice, dose and duration of EML-listed antibiotics for common infections in primary care and hospital facilities.
In 2019, the AWaRe classification was expanded beyond the WHO Model Lists of Essential Medicines, to include commonly used antibiotics globally.
Since then, the AWaRe classification has been reviewed and updated by WHO every 2 years.
WHO has also published the AWaRe antibiotic book which provides detailed guidance on the choice, dose and duration of EML-listed antibiotics for common infections in primary care and hospital facilities.
Frequently asked questions:
Why is it important to not use antibiotics as first-line treatment in conditions such as ear infections or sore throat?
In most cases, these types of infections do not require antibiotic treatment. They are often caused by viruses, against which antibiotics do not work. For these reasons, the recommended first-line treatment is taking medicine to relieve symptoms (e.g. analgesics). Symptoms usually improve within a few days without antibiotics. Not using antibiotics in such cases may help prevent antibiotic resistance. It is increasingly recognized that antibiotics are non-renewable resources that should be used wisely, carefully weighing potential benefits against the risk of antibiotic resistance and other adverse events. When used carefully, antibiotics will stay effective for use in serious cases and for vulnerable populations such as infants and the elderly.
What is the difference between first and second choices?
First choice antibiotics represents the best option in terms of effectiveness, harms and potential for resistance. In some cases, a second-choice antibiotic is also recommended. These antibiotics represent alternative options under some circumstances: they tend to be generally broader-spectrum antibiotics with higher resistance potential or less favorable risk–benefit ratios.
What does it mean that the impact of antibiotics on different diseases is associated with different balance of benefits and harms?
Consider the two examples of: ear infections and kidney infections. Most cases of ear infections in children are caused by viruses (for which antibiotics are not effective) and resolve spontaneously without antibiotics. For every 100 children treated, antibiotics provide a small reduction in pain beyond 24 hours in about 5 of them. This also means that the other 95 children will have no relevant benefit associated with antibiotic treatment. This small benefit must be weighed against the potential harms related to antibiotic use, both for the individual patient (e.g. allergic reactions and other side effects like diarrhea that will afflict 1 in every 5 patients treated)and for the community (e.g. increased antibiotic resistance that can be transmitted between patients). Furthermore, antibiotics also kill “good” bacteria with unclear long-term consequences.
Serious kidney infections on the other hand require prompt medical attention. If not treated properly, a kidney infection can permanently damage your kidneys or the bacterial infection can spread to your bloodstream and put your life at risk. For this reason, it is important that a kidney infection is treated in a timely manner with effective antibiotics. For these severe infections the benefits associated with antibiotic treatment largely outweigh the potential harms. However, an increasing number of people diagnosed with kidney infections have infections resistant to the standard class of antibiotic used in treatment hereby limiting antibiotic treatment options. This resistance is partly driven by the use of broad spectrum Watch group antibiotics for infections where Access group antibiotics would be preferable.
Serious kidney infections on the other hand require prompt medical attention. If not treated properly, a kidney infection can permanently damage your kidneys or the bacterial infection can spread to your bloodstream and put your life at risk. For this reason, it is important that a kidney infection is treated in a timely manner with effective antibiotics. For these severe infections the benefits associated with antibiotic treatment largely outweigh the potential harms. However, an increasing number of people diagnosed with kidney infections have infections resistant to the standard class of antibiotic used in treatment hereby limiting antibiotic treatment options. This resistance is partly driven by the use of broad spectrum Watch group antibiotics for infections where Access group antibiotics would be preferable.
Are the Watch and Reserve group antibiotics stronger than Access group antibiotics?
No. Antibiotics in the Access group remain the strongest, most effective antibiotics for many infections. The classification of antibiotics into one of the AWaRe groups is based on their impact on antibiotic resistance and need for surveillance of use and is not based on differences in clinical effectiveness.