Gonorrhoea 2021 - 2022
2021 & 2022 Annual Gonorrhoea Report
The national monitoring of gonorrhoea at Statens Serum Institut (SSI) is based on data extraction from the Danish Microbiology Database (MiBa). The MiBa contains results from culture and/or PCR or other nucleic acid amplification techniques (NAT), as all DCMs perform combined NAT for gonococci and Chlamydia trachomatis. In case of repeated positive samples from a person, a new gonorrhoea case is defined as the passing of more than 21 days since the latest positive finding.
Monitoring of laboratory-confirmed gonorrhea is supplemented by submission of isolates to the Department of Bacteria, Parasites & Fungi (BPF), Infection Preparedness at the SSI.
In addition to the laboratory-based monitoring, physicians have a statutory obligation to notify all gonorrhoea cases to the Notification System for Infectious Diseases (NSID), Department of Infectious Disease Epidemiology and Prevention (DEIP), SSI. Since 2022, this has been done electronically via the SEI2. The clinical notification forms request information that is not given as part of the laboratory data, e.g., mode of transmission, sexual orientation, country of infection and HIV status.
The Danish Microbiology Database (MiBa)
2021 recorded a total of 3,570 gonorrhoea cases, which was in line with the level recorded in 2020 (3,464 cases). In contrast, 2022 recorded a total of 5,204 cases, which constitutes a 46% increase from 2021. The gonorrhoea cases recorded in 2021 were distributed among 2,100 men and 1,168 women, as 3,011 (92%) had one case, 222 (7%) had two cases and 36 (1%) had more than two annual cases. In 2022, the 5,204 recorded cases were distributed among 2,939 men and 1,742 women, as 4,236 (91%) had one case, 383 (8%) had two cases and 62 (1%) had more than two annual cases.
The increase from 2021 to 2022 cannot be explained by increased testing activity as roughly the same number of samples was tested in both years.
The Notification System for Infectious Diseases (NSID)
In 2021, a total of 2,805 gonorrhoea cases were notified to the NSID, distributed among 2,637 persons, 931 women and 1,706 men, which means that 79% (3,570 recorded cases in the MiBa) of all gonorrhoea cases were notified to the NSID. This constitutes a 2-percentage point increase compared with 2020 when a total of 2,670 cases were notified (among a total of 3,464 recorded cases in the MiBa). In 2021, the notification percentage was higher than in the preceding 7 years, according to MiBa data, Figure 1.
In 2022, a total of 3,916 gonorrhoea cases were notified to the NSID, distributed among 2,314 men and 1,341 women, which constitutes a 40% increase (5,204 cases recorded in the MiBa) compared with 2021. 2022 recorded a notification percentage of 75%, which is a 4 percentage point decline compared with 2021.
For 2020 through 2022, the number of recorded gonorrhoea cases among men was highest among the 30-39-year-olds, even though a slight decline was recorded in their share of the total number of cases in 2022, to 25% from 27% in 2020 and 2021, Table 1. In 2021, the median age for men was 29 years, compared with 30 years in 2020 and 2022.
For women, the highest number of recorded gonorrhoea cases in 2021 was recorded among the 15-19-year-olds, which constitutes a shift from previous years, when the highest number of gonorrhoea cases was recorded among 20-24-year-old women, as was also the case in 2022. The median age for females was 24 years in 2020, 22 years in 2021 and 23 years in 2022.
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Figures 2a and 2b show gonorrhoea case incidence rates per 105 for 15-59-year-olds, by sex and partner’s sex, for 2021 and 2022. It is important to note that the incidence rates for men who have sex with women (MSW) and men who have sex with men (MSM) in Figure 2a and 2b, respectively, were calculated using the total male population as denominator. Assuming that approx. 5% of the male population are active homosexuals, this reduces the denominator 20-fold, thereby multiplying the incidence rate by 20 compared with what is shown in Figure 2a and 2b. This leaves MSM as the patient group that has recorded the highest incidence rate.
Overall, the 2021 figures show that the female incidence rate was higher for all ages below 20 years, whereas men recorded a higher incidence rate for all ages above 20 years. Women who have sex with women (WSW) were not included as an independent group, as the numbers were too small. A total of 20 cases of gonorrhoea were notified among WSW in 2021 and 22 cases in 2022.
Gonorrhoea in children
In 2021, a total of 12 cases of gonorrhoea were recorded in girls below 15 years of age and six cases among boys below 15 years of age. In 2022, 12 cases of gonorrhoea were registered among ten girls aged less than 15 years of age. No cases of gonorrhoea were registered in boys below 15 years of age in 2022. Among the registered gonorrhoea cases in both 2021 and 2022, several children had gonorrhoeal conjunctivitis; an important differential diagnosis to eye inflammation in neonates. However, gonorrhoeal conjunctivitis is seen in all age groups and is always a dangerous and potentially sight-threatening condition that needs to be diagnosed and treated acutely. The characteristic symptoms are inflammation of the eye with swelling of the eye and purulence.
Geographical distribution
In both years, the number of gonorrhoea cases was higher among men than among women in all areas, apart from West Jutland and North Jutland. Both the incidence rate (number of cases per 100,000 inhabitants) and the number of gonorrhoea cases were highest in the City of Copenhagen. For women, the number of cases was highest in East Jutland in 2021 and in the City of Copenhagen in 2022. An ever greater share of the gonorrhoea cases was recorded in women; 32% of all notified cases in 2020, 34% in 2021 and 35% in 2022.
In the City of Copenhagen and Copenhagen Subs., a considerably higher incidence rate was seen among men than among women in 2022, even though the incidence rate among women in the City of Copenhagen more than doubled from 2021 to 2022. In North Jutland, a similar increase was seen among women as the incidence rate nearly doubled. In the rest of Denmark, the incidence rates were comparable for men and women.
On the island of Bornholm, more cases were registered in 2022 than in 2021, particularly among women as no cases had been registered in 2021.
Modes of transmission 2021
Among the gonorrhoea cases notified in men, 789 (43%) were acquired by sex with women and 1,015 (55%) by sex with men. A single case of mother-to-infant transmission was notified; and for the remaining 51 (3%) cases, the mode of infection was not stated.
Among 949 notified cases in women, 909 (96%) were notified as having been acquired by sex with men, 20 (2%) as acquired by sex with women; and for the remaining 20 (2%) cases, the mode of transmission was not stated.
In 22 (2%) of the cases, the woman was pregnant, whereas 17 women and six men were notified as sex workers (six born in Denmark, 15 born abroad and two tourists).
Modes of transmission 2022
Among the 2,538 gonorrhoea cases notified in men, 1,160 (46%) were acquired by sex with women and 1,308 (52%) by sex with men. For the remaining 70 (3%) cases, the mode of transmission was not stated. Among the 1,378 gonorrhoea cases notified in women, 1,333 (97%) were acquired by sex with men and 22 (2%) by sex with women. A single case of mother-to-infant transmission was notified. In the remaining 22 (2%) cases, the mode of transmission was not stated.
In all, 23 (2%) of the notified women were pregnant. In 24 (<1%) of all notified cases, the infected person had stated being a sex worker, among whom 15 were women and nine were men. Seven of the sex workers were born in Denmark, 15 abroad and one was a tourist.
2022 recorded a considerable increase in the number of notifications for the MSW, MSM and women. However, the steepest increase was observed among women and MSW, Figure 3.
Sex, mode of transmission and country of transmission, 2021
In 2021, information on origin was available for 2,800 (>99%) of the notified gonorrhoea cases, of which 1,919 (68%) occurred in Danes, 718 (26%) in immigrants, 154 (5%) in second-generation immigrants and nine (< 1%) in tourists. Among the 984 gonorrhoea cases in MSM, 904 (92%) had become infected in Denmark. The corresponding share for MSW was 95% (736/774). Among women, 97% (903/927) of the gonorrhoea cases were registered as having become infected in Denmark.
Among the 144 gonorrhoea cases (120 men and 24 women) acquired abroad, 31 were registered as having become infected in Spain (including 23 MSM (74%) and 23 in Germany (including 17 MSM (74%)). The remaining 90 cases were distributed on 38 other countries in Europe, Africa, North-, Central, and South America, and Asia.
Sex, mode of transmission and country of transmission, 2022
In 2022, information about origin was available for 3,863 (99%) of the notified cases, and information about country of transmission was available for 3,846 (98%) of the notified cases. A total of 2,681 (69%) of the 3,863 cases occurred in Danes, 962 (25%) in immigrants, 218 (6%) in second-generation immigrants and two (>1%) in tourists. Among the 1,275 notified cases in MSM with information about country of transmission, 1,139 (89%) had become infected in Denmark. Among MSW, 1,072 (94%) had become infected in Denmark; and among women, 1,323 (97%) had become infected in Denmark.
Among 254 gonorrhoea cases (217 men and 37 women) acquired abroad, 42 were acquired in Germany (including 33 MSM (79%), 40 in Spain (including 30 MSM (75%), 15 in Thailand (including 12 MSW (80%), and the remaining 157 cases were acquired in 39 countries across the world, including Europe, Africa, Central-, and South America and Asia.
Gonorrhoea and HIV 2021
In 2021, information about HIV status was available for 2,210 (79%) of the notified gonorrhoea cases. Among 959 cases in MSM, 134 (14%) were HIV positive; including 129 with known HIV and five with newly acquired HIV. Among 569 MSW gonorrhoea cases for whom HIV status was stated, one (< 1%) was notified as a known HIV positive. Among 646 women for whom HIV status was stated, two were HIV positive.
Gonorrhoea and HIV 2022
In 2022, information about HIV status was available for 2,189 (56%) of the notified cases.
Among 1,210 cases in MSM, 200 (17%) were HIV positive; including 196 with known HIV and four with newly acquired HIV. A total of 194 (16%) of the MSM cases were HIV negative and receiving PrEP treatment. Among 418 MSW gonorrhoea cases for whom HIV status was stated, one (< 1%) was notified as a known HIV positive. Among the 541 gonorrhoea cases in women, four (<1%) were notified as HIV positive, among whom one had newly acquired HIV. Additionally, one gonorrhoea case was notified in a HIV-positive man for whom the mode of transmission was unknown.
Antimicrobial resistance
In 2021 and 2022, the SSI received gonococcal isolates from 1,405 and 1,843 unique cases of gonorrhoea that had been detected by culture in Danish DCMs. This corresponds to 39% and 35%, respectively, of all gonorrhoea cases recorded in MiBa in the two years in question. For comparison, isolates were submitted from 37% in 2020 and 34% in 2019. In Denmark, first-line treatment is monotherapy with ceftriaxone 500 mg administered intramuscularly as a single dose. In case susceptibility has been established, ciprofloxacin 500 mg administered orally may be used. The isolates were tested for ceftriaxone, azithromycin and ciprofloxacin resistance by determination of the minimum inhibitory concentration (MIC), mg/l and penicillinase formation, which indicates a high resistance to penicillin. The results hereof are presented in Figure 4.
In 2021 and 2022, ciprofloxacin resistance was detected in 48% and 40% of the isolates, respectively (the corresponding number was 43% in 2020 and 41% in 2019), whereas azithromycin resistance was detected in 3% of the isolates in both 2021 and 2022 (2% in 2020, 5% in 2019).
For azithromycin, as from 1 January 2019, the European Committee on Antimicrobial Susceptibility Testing (EUCAST) proposes a new delimitation of resistance (MIC > 1 mg/L) and susceptibility (MIC ≤1 mg/L) wherefore this drug should not be used as monotherapy in the treatment of gonorrhoea but always in conjunction with another effective antibiotic, mainly ceftriaxone.
Penicillinase formation was detected in 23% in 2021 and 14% in 2022 (17% in 2019 and 19% in 2020). In 2021, antimicrobial resistance was more frequently found in isolates from men than from women. Ciprofloxacin resistance was detected in 56% of the isolates from men and 32% of the isolates from women. For azithromycin, the corresponding numbers were 4% and 2%. In 2022, ciprofloxacin resistance was detected in 48% of the isolates from men and 28% of the isolates from women. Azithromycin resistance was detected in 3% of the isolates from men and 2% of the isolates from women. Resistance to both azithromycin and ciprofloxacin was found in < 1% of the isolates from women and 2% of the isolates from men.
Since 2016, ciprofloxacin resistance has followed an increasing trend until 2021 when it reached 48% before declining to 40% in 2022, which is the lowest level recorded since 2018. Azithromycin resistance followed a declining trend from 2018 to 2020, apart from a 0.9 percentage point increase in 2021, and the proportion with resistance remained at 2.9% in 2021 and 2022. The share of isolates that had penicillinase formation increased from 2020 to 2021, reaching 23%, which is the highest level recorded since 2003, but then declined to 14% in 2022, which is a lower level than the levels observed in 2020 (17%) and 2019 (19%), Figure 4.
In 2021 and 2022, no ceftriaxone resistance was detected in any isolates. In 2021, the highest recorded MIC value was 0.064 mg/L, and 86% of all isolates had a MIC value <0.008 mg/L, Figure 5.
In 2022, the highest recorded MIC value was 0.032 mg/L, and 94% of all isolates had a MIC value <0.008 mg/L, Figure 5.
Special antibiotics
As part of a joint EU effort, the Reference Laboratory annually tests slightly more than 100 consecutively collected isolates against an expanded panel of antibiotics. In 2021 and 2022, none of the 121 and 135 isolates, respectively, were resistant to cefixime (an oral cephalosporin), which is not marketed in Denmark.
In 2021, 1,089 of 1,405 unique isolates were linked to a notification to the NSID (notification dated less than 30 days after the isolate sampling date). The corresponding numbers for 2022 were 1,456 of 1,843 unique isolates. Owing to these numbers, it is possible to assess if an association exists between antibiotic resistance and the sexual orientation and the patient’s country of transmission.
2021 recorded the highest frequency of resistance to both ciprofloxacin and azithromycin in isolates from MSM, whereas the lowest frequency was seen in isolates from women. The share of isolates that were susceptible to both azithromycin and ciprofloxacin was lowest in isolates from MSM and highest in isolates from women.
2022 recorded the same pattern of ciprofloxacin as 2021. A slight increase was seen in azithromycin resistance for all three groups. The highest share of resistance was registered in isolates from MSM with 6% and the lowest share was recorded in isolates from MSW with 2%. The share of isolates with resistance to both azithromycin and ciprofloxacin was highest in the MSM group (4%) and lowest among MSW and women (1%). The share of susceptible isolates was lowest among MSM (22%) and highest among women (68%).
In 2021 and 2022, 1,003 isolates (92% of isolates linked to a NSID notification) and 1,355 (93%) cases were gonorrhoea acquired in Denmark, respectively. A total of 59 (5%) and 83 (6%) of these cases were acquired abroad, and for 27 (2%) and 18 (1%) cases with a corresponding isolate, respectively, the country of transmission was not stated. The distribution of antibiotic resistance is presented in Table 4a and 4b.
Special anatomical sampling locations
In 2021, the SSI received two isolates from synovial fluid; one isolate from an eye swab and two isolates from abscesses. In 2022, the SSI received one isolate from a blood culture and one isolate from an abscess.
This annual report is also described in EPI-NEWS 50/2023.