Introduction Despite the advancement of medicine and the absence of penicillin resistance, syphilis/congenital syphilis remains as a serious public health problem, especially in Brazil.

Objective To evaluate possible seasonality relation existence between temporal distribution of demand and positivity of VDRL tests at Miguelote Viana Public Health Central Laboratory (MVPHCL).

Methods This is a temporal series analytical cross-sectional study. Data of demand, VDRL tests positivity and worked days were collected in database related to the period 2006–2010 and analysed statistically through temporal series and hypothesis testing on tendency and seasonality. MVPHCL is reference to public health units of Niterói-Rio de Janeiro. This is an innovative research, since similar articles have not been found.

Results From January 2006 to December 2010, 22,943 VDRL tests were registered; on 2006: 22.85% (5,235); 2007: 20.16% (4,622); 2008: 20.15% (4,620); 2009: 19.27% (4,415), 2010: 17.57% (4,024). Worked days by month, in annual average, were 19.5 in 2006; 19.8 in 2007; 19.6 in 2008; 19.7 in 2009 and 19.3 in 2010. Monthly average of worked days was 21.2 in January, 17.2 in February, 21.6 in March 17 in April 16 in May, 18.4 in June, 21.8 in July 22, in August, 20.2 in September, 20.4 in October, 17.2 in November and 18.6 in December. Positivity annual average was in 2006: 19.83; 2007: 20.25; 2008: 21.58; 2009: 18; 2010: 18.25. Monthly positivity was 6.67% in January, 5.88% in February, 5.57% in March, 4.65% in April, 5.51% in May, 4.39% in June, 4.13% in July, 5.30% in August, 4.35% in September, 5.90% in October, 5.05% in November 5.30% in December. Carnival National Holiday occurred: February 28th, 20th, 05th, 24th, 16th from 2006 to 2010, respectively.

Conclusion Was not observed seasonal relation nor increase in demand and positivity of VDRL tests after Carnival over the studied years.

Disclosure of interest statement The STD sector is funded by the Federal Fluminense University, Brazil. No pharmaceutical grants were received in the development of this study.