Impact of COVID-19 pandemic responses on tuberculosis incidence: insights from Shantou, China – BMC Public Health

Our study utilized ITS analyses to assess the impact of measures taken to address the COVID-19 pandemic on the incidence of tuberculosis in Shantou, China. Overall, we found a significant decline in the incidence of tuberculosis during the pandemic. The stratified analysis showed that a significant drop in the incidence of tuberculosis among middle-aged and elderly individuals was observed during the pandemic. Due to the middle-aged people are the backbone of social productivity, and the elderly generally have other underlying diseases, they warrant an extra attention. The government may consider monitoring and managing middle-aged and elderly people more closely, like taking measures to restrict them from participating in large-scale gathering activities or wearing masks when going out on a daily basis. In terms of the occupational distribution, the unemployed and agricultural populations experienced the most significant declines in the incidence of tuberculosis during the pandemic. This may be due to the fact that the unemployed and those live in rural areas move relatively less therefore they have less chance of being infected.

Our study was preceded by several articles discussing the impact of the COVID-19 pandemic on tuberculosis, some of which observed trends similar to ours [5, 18]. For instance, the incidence rate of tuberculosis in Serbia declined from 9/100,000 in 2019 to 4.5/100,000 in 2020 [19]. Meanwhile, an American study observed that the reported cases of tuberculosis in 2020 has dropped by 20% compared with those in 2019 [20]. Additionally, a cross-sectional study in Shanghai found that the detection rate of tuberculosis significantly decreased during the COVID-19 pandemic [21]. After analyzing these pieces of literature, we discovered that the incidence of tuberculosis decreased to varying degrees in different countries during the COVID-19 pandemic. We speculate that these variations in the incidence of tuberculosis may be attributed to the differences in the approaches taken by various countries to combat the pandemic. For example, Sweden did not implement comprehensive lockdown measures but adopted a looser prevention and control strategy during the COVID-19 pandemic. The Swedish government emphasizes personal responsibility and voluntary compliance with public health measures, including social distancing, promoting the wearing of masks, and strengthening cleaning and disinfection measures [22]. In contrast, the Italian government implemented stringent lockdown measures, including restricting the movement of people, closing schools and businesses, and prohibiting large-scale activities in response to the pandemic.

At present, there is insufficient evidence to prove a direct causal relationship between the pandemic and the decline in the incidence of tuberculosis. The observed association between the pandemic and the decline may be explained by several speculative reasons. For example, in response to the pandemic, China issued the “Notice on the Prevention and Control of the Novel Coronavirus Pneumonia Pandemic” on January 26th, 2020. This notice emphasized the importance of personal protection and introduced specific measures such as wearing masks and practicing frequent handwashing. These measures aimed at minimizing the spread of the coronavirus may also reduce the spread of MTB and thus reduce the incidence of tuberculosis. More specifically, as the modes of transmission for COVID-19 and tuberculosis are similar, the preventive measures implemented to contain the spread of COVID-19 can also inadvertently contribute to preventing the transmission of tuberculosis. Other measures, such as non-contact services in public and commercial places, bans on public transport services, and restrictions on population movement have played a similar role.

While enforced measures to restrict population movement have proven effective in slowing the propagation of COVID-19, they may inadvertently lead to undesirable outcomes such as impeding timely medical care for those suffering from tuberculosis. This presents onerous challenges in the identification of tuberculosis cases due to limited transportation means and a decrease in medical visits. During the COVID-19 pandemic, the usage of public transportation in some cities has decreased. For instance, in cities like Italy and Spain, the usage of public transportation has decreased by 95% compared to the early stages of the pandemic [23]. According to a study conducted in Poland, global road transportation volume decreased by over 50% by the end of March 2020 compared to the same period in 2019. Similarly, compared to January 2020, public transport passenger volume decreased by 77% [24]. Another study in the same region also indicated a 66% reduction in individual travel time across all age groups during the COVID-19 period [23]. Besides, a study in Uganda found that through interviews with tuberculosis patients, 79.9% of them believed that the COVID-19 pandemic led to transportation restrictions, such as a lack of access to transportation to medical facilities, insufficient funds to cover transportation costs, and long distances to medical facilities, severely limiting their opportunities to access tuberculosis care services at treatment units [25]. On another note, the reassignment of healthcare resources and services and the prioritization of disease surveillance and reporting systems might have hindered the reporting of new cases. For instance, a retrospective study in South Africa found that during the COVID-19 pandemic, the utilization rate of primary healthcare services dropped significantly to 10.53% compared to previous periods [26]. A study in Pakistan similarly reached a similar conclusion [27]. Throughout the pandemic, the government focused predominantly on COVID-19 prevention and control, mandating all localities to enhance the storage and deployment of medical supplies like masks, goggles, and protective clothing to match the requirements for epidemic management. These measures could potentially adversely impact the detection and treatment of tuberculosis, as resource allocation has shifted towards addressing COVID-19, affecting the availability and accessibility of resources and services related to controlling tuberculosis.

Moreover, the relocation of healthcare personnel considerably reduced the workforce available for tuberculosis control, potentially leading to service interruptions like tuberculosis testing and rapid diagnosis, culminating in situations where tuberculosis patients cannot be diagnosed or treated promptly after arriving at the hospital. For example, a study in Turkey found that during the pandemic, there was a significant decrease in the incidence of tuberculosis, the number of screenings, and contact tracing efforts. It was noted that this trend might be attributed to the redirection of resources towards controlling COVID-19, which impacted the available workforce for tuberculosis control during the COVID-19 period. Hence, the decline witnessed in tuberculosis incidence amid the pandemic may not be legitimate but rather a consequence of inadequate reporting. To substantiate this hypothesis, a surge in tuberculosis visits after the pandemic would serve as confirmation, and it is imperative to conduct further investigations for validation.

Our study comes with a few limitations. Firstly, the quantity of tuberculosis cases gathered was dependent on a passive monitoring system, which could give rise to under-reporting and an undervaluation of actual tuberculosis patients. Secondly, despite the COVID-19 pandemic persisting, we designated the period of the pandemic as 2020–2021, disregarding the impact of its later stages. Thirdly, intervention measures and epidemics could differ across regions, making it challenging to directly extrapolate research outcomes from one area to another. Lastly, responses to the pandemic were diverse and complex, involving multiple levels and numerous measures, such as quarantines, medical resource allocation, and personnel movement restrictions. These policies may interconnect and mutually influence each other, making it challenging to attribute their effects solely to changes in the incidence of tuberculosis cases.