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Venereal disease research laboratory test-reactive syphilis cases from 2018 to 2022 in North India: Trends across pre-, during-, and post-COVID periods
*Corresponding author: Dr. Niti Khunger, Professor & Consultant Dermatologist, Department of Dermatology and Venereology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India. drniti@rediffmail.com
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Received: ,
Accepted: ,
How to cite this article: Goyal A, Lachyan A, Muralidhar S, Khunger N. Venereal disease research laboratory test-reactive syphilis cases from 2018 to 2022 in North India: Trends across pre-, during-, and post-COVID periods. J Skin Sex Transm Dis. doi: 10.25259/JSSTD_38_2024
Abstract
Objectives:
The objectives of the study are to evaluate the serological reactivity to syphilis among patients attending various departments in a tertiary care center and to analyze trends in venereal disease research laboratory (VDRL) test reactivity over a 5-year period (January 2018–December 2022).
Materials and Methods:
This retrospective observational study was conducted in the serology section of the Microbiology Department at a tertiary care hospital. Serological data from January 2018 to December 2022 were retrieved and analyzed. All samples were screened using the VDRL test. Reactive samples were further analyzed for titer levels and departmental distribution.
Results:
A total of 14,705 serum samples were tested using the VDRL test. Among these, 116 samples (0.78%) were reactive. The highest VDRL reactivity was noted in the Sexually Transmitted Infections (STIs)/Skin Outpatient department (1.75%), followed by “Others” (0.83%), Surgery (0.83%), General Medicine (0.48%), Antental Care (ANC) clinic (0.47%), and Emergency (0.45%). A male predominance was observed, with 59.48% (69/116) of reactive cases reported in males. The year 2019 showed the highest reactivity (1.04%), while the lowest was in 2021 (0.48%).
Limitations:
Confirmatory treponemal tests were not performed for all VDRL-reactive cases, and clinical histories were limited.
Conclusion:
Although the overall VDRL reactivity rate was low, higher rates among STI and ANC attendees underscore the importance of sustained screening and follow-up. Improved confirmatory diagnostics and record-keeping are necessary to reduce missed diagnoses.
Keywords
Coronavirus disease 2019 (COVID-19)
Epidemiology
Seroprevalence
Sexually transmitted infection
Syphilis
Venereal disease research laboratory test
INTRODUCTION
Syphilis, caused by the bacterium Treponema pallidum, continues to be a significant public health issue despite being curable with antibiotics. The diversity in clinical manifestations and mimicry of other conditions complicates timely diagnosis and treatment. Routine screening and early treatment are crucial to prevent transmission and adverse outcomes, especially congenital syphilis.[1]
The venereal disease research laboratory (VDRL) test is a non-treponemal, cost-effective serological test commonly used for screening and monitoring syphilis treatment response.[1] However, it requires confirmation by treponemal-specific assays.[2]
This study evaluates the VDRL-reactive rates among patients over a 5-year period at a tertiary sexually transmitted disease center in North India, focusing on trends across the preCOVID, during-COVID, and post-COVID periods. The findings may inform targeted sexually transmitted infection (STI) control strategies in India.
MATERIALS AND METHODS
Study design and setting
This retrospective cross-sectional study was conducted at the Regional Apex STI Centre of Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi – a tertiary care facility receiving patients from various regions, including rural and urban settings.
Study period and population
Serological records were reviewed from January 2018 to December 2022. Serum samples were collected from departments such as Dermatology/STI Outpatient department, ANC clinic, General Medicine, Emergency, Surgery, and other miscellaneous departments.
Laboratory testing
All samples were screened using the VDRL test. Reactive results were recorded along with titer levels. Treponemal confirmation tests (TPHA and FTA-ABS) were not performed.
Data collection
The following parameters were extracted: Age, gender, referring department, and VDRL reactivity. Data were anonymized and analyzed using Microsoft Excel.
RESULTS
Out of 14,705 serum samples tested, 116 (0.78%) were VDRL reactive.
Table 1 shows that the highest VDRL positivity rate was observed in patients attending the STI/Skin Outpatient department (OPD) (1.75%), followed by the “Others” category (0.83%) and the Surgery department (0.53%). The antenatal clinic (ANC) had a lower positivity rate of 0.47%, comparable to general medicine (0.48%) and emergency (0.45%). Overall, out of 14,705 samples tested across departments, 116 were VDRL reactive, with a cumulative positivity rate of 0.78%.
| Department | Total tested | Reactive cases | Positivity rate (%) |
|---|---|---|---|
| STI/Skin OPD | 3,250 | 57 | 1.75 |
| ANC clinic | 4,250 | 20 | 0.47 |
| General medicine | 2,500 | 12 | 0.48 |
| Emergency | 2,000 | 9 | 0.45 |
| Surgery | 1,500 | 8 | 0.53 |
| Others | 1,205 | 10 | 0.83 |
| Total | 14,705 | 116 | 0.78 |
STI: Sexually transmitted infection, Skin OPD: Skin outpatient department, ANC: Antenatal care.
Table 2 indicates that out of the 116 VDRL-reactive cases identified, 69 (59.48%) were male and 47 (40.52%) were female.
| Gender | Reactive cases | Percentage |
|---|---|---|
| Male | 69 | 59.48 |
| Female | 47 | 40.52 |
| Total | 116 | 100 |
Table 3 shows a year-wise distribution of VDRL-reactive cases and corresponding positivity rates. The highest positivity rate was observed in 2019 (1.04%), followed by a gradual decline during the COVID-19 pandemic period, reaching the lowest in 2021 (0.48%). A slight increase was noted again in 2022 (0.63%).
| Year | Reactive cases | Positivity rate (%) |
|---|---|---|
| 2018 | 31 | 0.91 |
| 2019 | 35 | 1.04 |
| 2020 | 28 | 0.77 |
| 2021 | 16 | 0.48 |
| 2022 | 18 | 0.63 |
| Total | 116 | 0.78 |
Table 4 displays the distribution of VDRL titers among 116 reactive cases. A majority of patients (79.31%) had low titers (≤1:8), suggesting either treated syphilis, late syphilis or biological false positive. Moderate titers (1:16) were seen in 12.93%, while high titers (≥1:32), which may indicate active or recent infection, were noted in a smaller subset (7.76%).
| Titer | Cases | Percentage |
|---|---|---|
| ≤1:8 | 92 | 79.31 |
| 1:16 | 15 | 12.93 |
| 1:32 | 5 | 4.31 |
| >1:32 | 4 | 3.45 |
| Total | 116 | 100 |
Table 5 presents the distribution of VDRL-reactive cases across different age groups. The highest number of cases was reported in the 20–29-year age group (42.5%), followed by 30–39 years (30.5%). Individuals aged below 20 years constituted 10.34% of the cases. A gradual decline was observed in older age groups, with 12.07% in the 40–49-year range and only 5.17% in those aged ≥50 years.
| Age group (years) | Cases | Percentage |
|---|---|---|
| <20 | 12 | 10.34 |
| 20–29 | 49 | 42.5 |
| 30–39 | 35 | 30.5 |
| 40–49 | 14 | 12.07 |
| ≥50 | 6 | 5.17 |
| Total | 116 | 100 |
DISCUSSION
This study reports a VDRL-reactive rate of 0.78% across 5 years. Given the absence of confirmatory treponemal testing, these figures reflect serological reactivity and cannot be equated to definitive syphilis prevalence.[2]
The higher VDRL positivity in 2019 may reflect improved health-seeking or diagnostic access before pandemic disruptions. The dip in 2021 aligns with pandemic-related reduced outpatient services, which may have skewed the demographics of those tested and delayed detection.[3,4]
The majority of reactive titers were low (≤1:8), suggesting a mixture of latent or previously treated infections and biological false-positives.[5]
Men accounted for 59.48% of reactive cases, consistent with epidemiological patterns where men – particularly men who have sex with men – exhibit higher syphilis incidence.[5] The 40.52% female positivity, including pregnant women screened at ANC clinics, supports ongoing routine antenatal syphilis screening .[6]
Most cases were concentrated in the 20–39 age range, aligning with international data linking sexual activity and risk in young adults.[7]
Limitations
Retrospective design: Dependent on the completeness of past records
No confirmatory testing: Limits specificity and may overestimate actual syphilis prevalence
Limited clinical data: Lack of correlation with clinical history or sexual behavior
Sampling bias: Over-representation of certain departments
Generalizability: Data limited to a single institution.
CONCLUSION
This study highlights the need to sustain syphilis surveillance, especially among patients attending STI and ANC clinics. Future surveillance efforts should incorporate clinical data and broader population sampling.
Acknowledgment:
We acknowledge the support from the Regional Apex STI Centre, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India, and we thank all the healthcare workers and participants involved in this study.
Ethical approval:
The Institutional Review Board approval is not required since it was a cross-sectional retrospective study.
Declaration of patient consent:
The authors certify that they have obtained all appropriate patient consent.
Conflicts of interest:
There are no conflicts of interest.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
Artificial intelligence (AI), specifically ChatGPT, was used solely for the purpose of rephrasing and language refinement during the preparation of this manuscript. All AI-assisted content has been carefully reviewed, cross-checked, and validated by the authors. No original scientific content, data interpretation, or conclusions were generated by AI.
Financial support and sponsorship: Nil.
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