Search for asymptomatic carriers of SARS-CoV-2 in healthcare workers during the pandemic: a Spanish experience

Abstract

Background Asymptomatic carriers of SARS-CoV-2 can be a vehicle for transmission of the infection. This fact is of particular importance in the case of healthcare workers (HCWs). Design Cross-sectional study in HCWs in a medium size hospital in the South of Spain. Methods between April 15 and 25, 2020, naso and oropharyngeal PCR determination was performed together with IgG and IgM antibody determination by immunochromatography to the HCWs of the Costa del Sol Hospital in Marbella of the units involved in patient care with CoVID-19: Emergencies, Intensive Care and Anesthesia, Internal Medicine and Pneumology. Other units not directly involved in the care of these patients were offered to participate. On the day of sampling, a health questionnaire was answered, reporting symptoms on the same day and in the previous fourteen days. Results 498 HCWs were studied. Two individuals were detected with PCR for SARS-CoV-2 positive. Both were asymptomatic on the day of sampling, but one of them had had a CoVID-19 compatible picture in the previous two weeks and had positive IgG and IgM; therefore, only one subject was truly asymptomatic carrier (0.2%). 9 workers with positive IgG (1.8%) were detected. Conclusions the prevalence of asymptomatic carriers among health workers of the services directly involved in the care of patients with CoVID-19 was very low in our center. This type of strategy can be one more tool in controlling the pandemic.

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 ].…”

“…All studies except one [ 31 ] used a convenience sample, while response rate ranged from 47.7% [ 19 ] to 100% [ 36 , 60 ]. Forty-two studies were conducted in hospitals [ [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , 26 , 27 , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] , [46] , [47] , [48] , [50] , [51] , [52] , [53] , [54] , [55] , [56] , [57] , [58] , [59] , [60] , [61] , [62] ], four studies in primary care facilities and hospitals [ 14 , 25 , 28 , 49 ], two studies in primary care facilities [ 35 , 62 ] and one study in cancer centers [ 59 ]. Thirty-five studies were published in journals [ [14] , [15] , [16] , [17] , [18] , [19] , [20] , <...>…”

Routine Asymptomatic SARS-CoV-2 Screen Testing of Ontario Long-Term Care Staff After COVID-19 Vaccination

“…However, the results are consistent with other asymptomatic testing campaigns. [19][20][21][22] There are several potential harms of routine asymptomatic screen testing including staff physical discomfort and injury from frequent nasopharyngeal swabbing, staff behaviour change associated with knowledge that screen testing is negative, and a high rate of false positive results which can exacerbate staffing shortages and cause unnecessary testing and isolation of staff and residents. Universal staff screen testing can also impact provincial laboratory testing capacity and test turn-around times.…”

“…These Ontario findings align with multiple Canadian and international studies demonstrating a <0.5% positivity rate in asymptomatic individuals tested for SARS-CoV-2 in low incidence settings (COVID-19 Provincial Diagnostic Network Laboratories, personal communication). [19][20][21][22]…”