Low seroprevalence of SARS-CoV-2 infection among healthcare workers of the largest children hospital in Milan during the pandemic wave

Abstract

Lombardy, Northern Italy, was the first region within a Western country to be severely hit by the spread of severe acute respiratory coronavirus virus 2 (SARS-CoV-2). The coronavirus disease 2019 (COVID-19) pandemic started officially in Italy on February 21, 2020, 1 although today it is recognized that the virus had been circulating unnoticed for at least a month prior to that date. 2,3 Several nosocomial outbreaks occurred in the first phase of the epidemic, and healthcare workers (HCWs) were the most vulnerable cohort for COVID-19 due to frequent and close contact with COVID-19 patients without, at least in an initial phase, adhering to strict hygienic measures. We conducted a cross-sectional seroprevalence study among the HCWs of the largest pediatric hospital in Milan during the period of maximum epidemic activity, when Lombardy accounted for 37% of cases and 53% of deaths in the country. 4 a Authors of equal contribution. Cite this article: Amendola A, et al. (2020). Low seroprevalence of SARS-CoV-2 infection among healthcare workers of the largest children hospital in Milan during the pandemic wave.

Seroprevalence of SARS-CoV-2 antibodies and associated factors in healthcare workers: a systematic review and meta-analysis

“…The majority of studies was conducted in Europe (n=31), and then in North America (n=9), Asia (n=6), and Africa (n=3). In particular, nine studies was conducted in USA [ 14 , 15 , 24 , 26 , 27 , 29 , 32 , 34 , 40 ], eight studies in Italy [ 23 , 28 , 30 , 36 , 44 , 45 , 56 , 57 ], seven studies in United Kingdom [ 16 , 17 , 20 , 25 , 33 , 59 , 61 ], five studies in Germany [ 21 , 35 , 42 , 43 , 46 ], four studies in Spain [ 31 , 38 , 49 , 52 ], and three studies in and Japan [ 53 , 58 , 62 ], Belgium [ 18 , 19 , 22 ] and China [ 47 , 48 , 51 ]. Twenty-nine studies did not report the response rate [ [15] , [16] , [17] , 20 , 24 , [26] , [27] , [28] , [29] , [30] , [32] , [33] , [34] , 38 , [40] , [41] , [42] , [43] , 45 , 47 , 48 ,…”

“…Mean age of HCWs ranged from 31.2 [ 51 ] years to 47.9 years [ 57 ], while sample size ranged from 25 [ 40 ] to 40,329 HCWs [ 14 ]. Regarding the study design, 26 studies were cross-sectional studies [ 14 , 15 , 18 , 19 , 21 , [23] , [24] , [25] , [27] , [28] , [29] , [30] , [31] , [32] , [34] , [35] , [36] , [37] , 39 , 44 , 47 , 52 , 54 , 58 , 60 , 61 ], 20 studies were prevalence studies [ 17 , 26 , 33 , 38 , [40] , [41] , [42] , [43] , 45 , 46 , [48] , [49] , [50] , [51] , 53 , 55 , 56 , 57 , 59 , 62 ], and three studies were cohort studies [ 16 , 20 , 22 ]. All studies except one [ 31 ] used a convenience sample, while response rate ranged from 47.7% [ 19 ] to 100% [ 36 , 60 ].…”

Cross-sectional prevalence of SARS-CoV-2 antibodies in healthcare workers in paediatric facilities in eight countries

“…[ [4] , [5] , [6] , [7] ] As relatively few children globally have been admitted to hospital with COVID-19,[ 8 ] staff working in paediatric facilities have been unlikely to face a significant risk of exposure from their patients. [ 9 ] Only two studies of seroprevalence in paediatric HCWs have been published to date. In Barcelona, Spain, seroprevalence rates of 4% were discovered,[ 10 ] similar to the rate in a population-based random sample from the general population in Barcelona (5·4%) analysed at roughly the same time (March/April 2020) while in Argentina, the rate in Paediatricians from a single children’s hospital 3 months into the pandemic was 0.9%.…”

SARS-CoV-2 infection dynamics in Denmark, February through October 2020: Nature of the past epidemic and how it may develop in the future

“…The size of the recovered populations at any given time depends on both the number of recovered infected individuals and on the decay rate of the average immunological memory of symptomatic ξ s and asymptomatic ξ a individuals, recall Eqs. (1). This means that with only one serological measurement at t 1 infinitely many combinations of ρ s and ξ s , ξ a fit the observed serological prevalence.…”

“…Since there likely is a significant difference in the immunological memory for the symptomatic and the asymptomatic infected we have disaggregated the recovered population into R a and R s with short and long immunological memory respectively. The rate of recovered population members once again becoming susceptible is given by ξ y R y , y = a, s, which is reflected in the positive terms in the first expression in equation set (1).…”