Is COVID-19 affecting the epidemiology of syphilis in Belgrade?

Sir,

The first case of coronavirus 2019 disease (COVID-19) in Serbia was reported on 6^th March 2020, with the Serbian government declaring a state of emergency and nationwide lockdown on 15 March 2020.¹ This included various social distancing measures, some of which still remain after the lockdown was lifted on 6^th May 2020. Although the City Institute for Skin and Venereal Diseases in Belgrade is a reference centre for sexually transmitted diseases, during the lockdown it remained open only for emergencies. Late June and November saw the reinstatement of even stricter social confinement measures, as two new waves of infection broke out. This study aims to assess whether COVID-19 affected the epidemiology of syphilis in Belgrade. We used data on newly registered cases of syphilis diagnosed at any stage of the disease during the study period of three years - 2018, 2019 and 2020. Data collected included age, gender, sexual orientation, human immunodeficiency virus (HIV) status and stage of syphilis. Chi-square test and t-test were used in statistical analysis. The investigation was approved by the Ethical Committee of the City Institute for Skin and Venereal Diseases.

Between 2018 and 2020, 314 new cases of syphilis were diagnosed in the City Institute for Skin and Venereal Diseases in Belgrade comprising 100 cases in 2018, 89 cases in 2019 and 125 in 2020 [Table 1]. In comparison with 2018 and 2019, patients with syphilis diagnosed in 2020 did not significantly differ in their median age, male/female ratio, sexual orientation, HIV status and stage of the disease. The mean age of patients in 2020 was significantly lower compared to the mean age of patients in both 2018 and 2019 (P < 0.05) [Table 1]. In fact, the comparison of age-groups of patients in the observed years showed that in 2020, number of patients of the age of 50 years or more was less when compared to 2018 and 2019 (P = 0.011 and P = 0.047, respectively).

During the period from 2009 to 2018, the number of newly diagnosed syphilis cases in Belgrade was increasing and the highest crude rate was recorded in 2018.² Compared to 2018 and 2019, the number of syphilis cases increased in 2020 by 25% and 40.5%, respectively. The actual number of new syphilis cases in 2020 is probably even higher because people had limited access to the public health service and some infected persons might have sought care in the private sector.

Our results are in line with data from Bologna where the percentage of new syphilis cases and other sexually transmitted infections had significantly increased³ suggesting that the lockdown had not actually interfered with high-risk sexual behaviour. Reports from some European cities have shown that the incidence of sexually transmitted infections decreased during the lockdown,^4,5 which could be explained by restricted movement or reduced access to health services for people with sexually transmitted infections. However, Sacchelli et al.⁶ reported in their study that no significant change in the incidence of sexually transmitted infections has occurred during the pandemic.

The expected decrease in the number of newly diagnosed syphilis cases in Belgrade, due to the pandemic induced restrictive measures, did not probably occur because during the last 10 years, in our population syphilis has predominantly been diagnosed in men who have sex with men² who can easily reach sexual partners through mobile dating applications and do not require public places to meet.

Compared to the previous two years, the lower number of syphilis cases in those with age 50 years or more in 2020 could be explained by the fact that older people due to fear of COVID-19, have shown greater responsibility towards their own health and limited their social contacts with household members only (people over 65 were completely forbidden to go out during the lockdown) thereby reducing their chance to come into potential sexual contact.

Stress, anxiety, depression and isolation caused by the pandemic has certainly affected the sexual behaviour, changing sexual habits and caused more frequent visits to porn sites, sex toys and cybersex consumption.⁷ A study conducted in Israel⁸ has shown that men who have sex with men limited kissing their sexual partners and increased the use of sex phones, webcam sex and porn consumption during lockdown. The majority of our patients with syphilis had unprotected sex during the lockdown and explained that sex was a way to relieve frustration due to the pandemic and that they participated in private gay orgies. In conclusion, the increased number of new syphilis cases in our institute indicates that the pandemic did not significantly affect the risky behaviour of the majority of the population, with the exception of those who were 50 and more years old.