A significant drop in the incidence of adult pleural infections during the first year of the COVID-19 pandemic was most likely because of reduced viral transmission from social distancing measures, researchers at Oxford University have concluded.

A team led by Dr Eihab Bedawi, a clinical research fellow in pleural disease looked at data collected by specialist pleural units across the UK that were already screening for pleural infections as standard practice.

They found that the number of pleural infection cases recorded in March 2020 to February 2021 (post-COVID) was 33% lower than that recorded for the same period of 2020 (pre-COVID; 124 cases vs 184 cases, respectively).

Also, while 25% of pleural infection cases were diagnosed during the influenza season (December, January and February) in the pre-COVID period, this figure dropped to 12% post-COVID period.

Patient demographics, infection setting, immunosuppression and median RAPID score were similar in both groups, and while the median interval between symptom onset and hospital attendance was slightly longer in the post-COVID cohort (14 vs 10 days, respectively), the difference was also not statistically significant.

There were, however, significantly greater proportions of pleural fluid purulence (40% versus 27%) and culture-positive infections (39% vs 27%) in the post-COVID period, which the researchers suggest might be due to poorer access to antibiotics in the community setting during this time.

According to the authors, “the potential role of public health measures in reducing pleural infection incidence is intriguing and one that has not been specifically explored in the existing literature”.

“It is highly likely that decreased social mixing, shielding of older, more vulnerable patients with additional comorbidity, often at increased risk of pleural infection, as well as social distancing measures have had, in combination, a beneficial impact.”