The study has important limitations:  

• A very important limitation in this study is blinding. The nursing staff is in charge of implementing the intervention and assessing the results, and is not blinded to the group to which the participants belong. They should have been in order to ensure that the intervention and follow-up were exactly the same between groups. In this study, the nurses know which patient they are following by telephone (whether the participant receives e-cigarettes or standard treatment), and can therefore modulate the intervention.  
• The intervention is not strictly comparable between groups and is not recorded in detail. The comparison group is given 50 euros to spend on whatever they want, but it is not known whether they have spent it on detoxification treatments. In addition, the complementary intervention with nicotine patches seems not to be recorded, so it is not clear how many people in both the intervention and control groups have used nicotine patches, what type and for how long.  
• It would have been interesting to have a comparison group with pharmacological treatment.  
• It has not been recorded which nicotine device the subjects in the intervention group have chosen. In other words, it could be the case that they are receiving more nicotine in e-cigarettes than with the conventional cigarette they were using before the intervention. This is a key fact that we do not know.  
• In the assessment of the main outcome there are many losses, understood as the lack of biochemical verification of abstinence. This casts doubt on the validity of the results, as we do not know the causes of these losses.  

There is a 12% difference in abstinence duration in favour of the e-cigarette. This magnitude is relatively small and we do not know if it is due to the possible greater addiction in some versus others. This is also counterbalanced by the greater adverse effects in the intervention group.  

It is very striking that the study, which has completed fieldwork in 2021, is only reported to give results at six months, when it is indicated that the follow-up would be much longer term. However, none of this information is given, when the data should already be available, as at least two years have passed for all participants. The reasons for this omission of information should be given.   

There are also issues related to the subjects included. They are relatively young smokers (only 25% are older than 50 years), have limited addiction (Fagerstrom scale 4 out of 10), and a high educational level. This does not represent the standard smoker, who smokes much more, has a higher addiction and a lower educational level.  

In conclusion, while suggesting that e-cigarettes may be beneficial for smoking cessation, this study has several limitations and its results should be taken with caution.

Electronic cigarettes, also known as vapers, are devices equipped with an electrical heating element that heats a liquid containing propylene glycol, glycerine, additives and often nicotine, to generate an aerosol that is inhaled like cigarette smoke. The global market for these devices, marketed as consumer products, has been growing rapidly over the last decade and was worth more than 20 billion euros in 2022. 

The paper just published in the New England Journal of Medicine shows the results of a clinical trial comparing quit rates of smoking and other nicotine products in a group of 1,246 smokers of five cigarettes a day or more, who were randomly assigned to two groups. Subjects in the control group received behavioural treatment over an eight-week period that included information on the use of different smoking cessation medications, while the intervention group was also provided with free e-cigarettes and liquids to be used for a period of six months. After this time, the proportion of subjects who remained smoke-free in the intervention group was significantly higher than that observed in the control group. However, the proportion of participants who, at the end of the follow-up period, had not used any nicotine products (in the form of tobacco, e-cigarettes or medication) for at least one week was higher in the control group than in the experimental group. 

The results of this study add to those of other research that, under the conditions of a clinical trial, suggest that e-cigarettes could improve the results of conventional smoking cessation treatment. A high proportion of smokers who quit smoking continue to use nicotine-containing e-cigarettes regularly after six months, in contrast to the usual case of nicotine-containing drug therapy, where drug treatment is withdrawn before this time is reached. Thus, the potential help of e-cigarettes for smoking cessation contrasts with the risks of continued use in terms of potential relapse or the long-term harmful effects of nicotine and other toxic components of the aerosols emitted by these devices. Moreover, even in the case of smoking cessation medications, it is difficult for the benefits obtained under the demanding conditions of a clinical trial to be observed also in real-life conditions, where many smokers present more complex clinical situations and cannot access intensive professional support. 

The circumstances under which e-cigarettes are made accessible to the population in our environment, where large multinational tobacco companies are involved in the promotion and marketing of some of the most successful products, have also favoured the use of these devices among young people and adolescents, exposing them to a higher risk of developing nicotine addiction, favouring the progression towards the use of conventional tobacco products and thus undermining the progress that is needed to reduce the enormous burden of disease and mortality caused by tobacco worldwide.

This well-conducted trial adds to the growing evidence base showing that e-cigarettes can help people to stop smoking. People who received the intervention (free e-cigarettes and e-liquids plus usual care) were 77% more likely to quit smoking for at least six months than those in the control group (usual care). It also assessed the safety of using e-cigarettes to quit, finding a slightly higher rate of non-serious adverse events in the intervention vs. control group, but no difference in the rate of serious adverse events (i.e., things that resulted in hospitalisation, ‘substantial incapacity’, or death). These findings should provide further reassurance to people who smoke and healthcare professionals that e-cigarettes can be used as an effective tool for stopping smoking without substantial risks to health.

This study adds to the growing number of high-quality trials showing that e-cigarettes are an effective smoking cessation aid, nearly doubling cessation rates compared with existing treatment. Crucially, this is the first study of its kind in Central Europe, confirming that this effect is observed across different context and in countries with different policy environments. This study also provides further insights into the safety profile of e-cigarette use for smoking cessation. Despite the fact that the control intervention was standard-of-care smoking cessation counselling with very little use of e-cigarettes or nicotine replacement therapy at six month follow-up, compared with half of intervention participants still using e-cigarettes, no differences in respiratory symptoms were observed between the intervention and control group.