COVID19-vaccination affects breath methane dynamics

Abstract

Methane (CH4) is well known as a component in the exhaled breath of humans. It has been assumed for a long time that formation of CH4 in humans occurs exclusively by anaerobic microbial activity (methanogenesis) in the gastrointestinal tract. A fraction of the produced CH4 is excreted via the lungs and can then be detected in the breath. However, recent studies challenge this view by showing that CH4 might also be produced endogenously in cells by oxidative-reductive stress reactions. Thus, an increased and fluctuating level of breath CH4 compared to the base level of an individual might also indicate enhanced oxidative stress levels. Thus, monitoring breath CH4 levels might have great potential for in vivo diagnostics. Generally, vaccines generate a strong immune response including the production of pro-inflammatory cytokines. To evaluate the effect from current vaccines against COVID-19 on breath CH4 dynamics, breath CH4 was monitored from 12 subjects prior and after the injection of several COVID-vaccines. Prior to COVID-19 vaccination the concentration of breath CH4 was frequently measured by gas chromatograph flame ionization detection (GC-FID, with analytical precision better than 10 parts per billion, ppbv) to obtain the individual variation range of breath CH4 for each subject. Following vaccination, CH4 breath samples were collected at high frequency for a period of 14 days. All subjects monitored showed a strong response in breath CH4 release within 1 to 72 hours after vaccination including shifts and high fluctuations with maximum peaks showing a factor of up to {+/-}100 compared to base values. Thus, it is highly likely that the observed changes in breath CH4 are coupled to immune responses following Covid-19 vaccination. These preliminary results strongly support the hypothesis that non-microbial methane liberation and utilisation in the human body might be also linked to cellular processes and stress responses independent of classical microbial methanogenesis. Thus, CH4 might be used as a breath biomarker for specific immune responses and individual immune states.