Three years on from the start of the COVID-19 pandemic, it seems we still have more questions than answers, on important issues such as the origins of the virus, and our most effective tools in fighting it. News of two recent studies only served to heighten the uncertainty.

Last month, Cochrane published a new review on what's known about masking, now three years into the COVID pandemic. Cochrane is known to be the world's largest and most respected organisation for evaluating health interventions. Their reviews represent a gold standard source of data that can be applied to clinical practice. The latest review is an update to Cochrane's last report on the physical interventions meant to reduce the spread of respiratory viruses, published in 2020. It highlights what the authors describe as "research gaps" concerning the effectiveness of masks, and the overall "uncertainty about the effects of face masks."

The review concluded: "Wearing masks in the community probably makes little or no difference to the outcome of laboratory-confirmed influenza/SARS-CoV-2 compared to not wearing masks." Although that conclusion doesn't definitively prove that masks do not help- mask critics have latched on to the findings and used them to question the guidance from various health authorities during the pandemic. Rather, the review calls attention to the limitations of the research-including how difficult it is to use randomised control trials to study the effectiveness of masks-and what this lack of evidence means when it comes to making decisions about public health.

Critics have several issues with the Cochrane Review's methodology. For example, just six of the 78 trials included were conducted during the COVID-19 pandemic. The others focus on other respiratory illnesses, like the flu. In a February subcommittee hearing, the US Centres for Disease Control director Rochelle Walensky listed this element as one of the review's limitations. The authors acknowledge that these studies were "conducted in the context of lower respiratory viral circulation and transmission compared to Covid-19."

The other controversy that continues to brew concerns the origins of the virus. According to the Wall Street Journal, an updated and classified 2021 US energy department report has concluded that the coronavirus behind the recent pandemic most likely emerged from a laboratory leak but not as part of a weapons programme. The report's conclusion runs counter to that of several scientific studies as well as reports by a number of other US intelligence agencies. It should also be pointed out that the DoE has 'low confidence' in that assessment, and it did not change the minds of any of the other agencies. According to the US government's own guidance: "A low confidence level generally indicates that the information used in the analysis is scant, questionable, fragmented, or that solid analytical conclusions cannot be inferred from the information."

While some scientists are open to the lab-leak theory, others continue to believe the virus came from animals, mutated, and jumped into people - as has happened in the past with viruses. Experts say the true origin of the pandemic may not be known for many years - if ever. This means it is likely to remain a bone of contention for a long time. In the meantime, expect the politicking over the virus that has killed nearly 7 million people around the world since being discovered in the Chinese city of Wuhan in December 2019, to continue.