Childhood exposures to discarded needles and other objects potentially contaminated with blood-borne pathogens in Toronto, Canada

Abstract

Background

Exposure to discarded needles or other objects put children at risk for infection with blood-borne pathogens (BBP), including human immunodeficiency virus (HIV), hepatitis B (HBV) and hepatitis C.

Objective

The purpose of this study was to retrospectively analyze the epidemiology, management and outcome of children following such exposures in the greater Toronto community setting.

Methods

A retrospective study of children <19 years of age who had community-based exposure to objects that could contain BBP between January 2001 and December 2014. Sexual and hospital inpatient exposures were excluded. Patients were identified by medical record review of all children who had HIV testing performed.

Results

Sixty-six community-based exposures to objects potentially contaminated with BBP were identified (71.2% needlesticks). The median age was 6.3 years (interquartile range 3.8, 7.8). Exposures occurred outdoors in the community (45.5%), in schools (30.3%), homes (15.2%) and community/outpatient clinics (9.0%). Of 11 (16.7%) identified source subjects, 7 were known to be HIV infected. HIV post-exposure prophylaxis was prescribed to 22 (33.3%) children; 15 (71.4%) completed the course. Only 41.2% of previously unvaccinated children were documented to have completed a full HBV vaccine series post-exposure. No blood-borne infections were documented, but only 60.6% had documentation of adequate follow-up testing.

Conclusions

Enhanced public health interventions in schools and other community settings are needed to reduce childhood risk of exposure to needlesticks or other objects potentially contaminated with BBP.

Percutaneous or mucocutaneous exposures to discarded needles or other objects potentially contaminated with blood-borne pathogens (BBP) are an important public health problem as they put children at risk for infection with BBPs. Based on data from the health care setting, the risk of transmission for human immunodeficiency virus (HIV), hepatitis C virus (HCV) and hepatitis B virus (HBV) following percutaneous injury involving a known infected source has been estimated as 0–2.38%, 0–10.3% and up to 60% (highest in HBeAg positive), respectively (1–3). The risk of transmission of HIV following mucous membrane exposure is about 0.09% (4).

The current Canadian Paediatric Society (CPS) guidelines recommend use of HIV-post-exposure prophylaxis (HIV-PEP) following exposure to discarded needles only in high-risk cases where the source is considered likely to have HIV, the incident involved a needle and syringe with visible blood and when blood may have been injected (5). In situations where the source is unlikely to have HIV, there is no visible blood in the device or the injury is superficial, HIV-PEP is not generally recommended. The aim of this study was to retrospectively analyze the epidemiology, management and outcome of children following community exposures associated with potential risk of BBP transmission in the Greater Toronto Area.

METHODS

Patient population and data collection

Individuals were eligible if they were less than 19 years of age and had community-associated needlestick injury (CA-NSI) or exposures to other objects potentially contaminated with body fluids that could contain BBP between January 2001 and December 2014. Sexual and hospital inpatient exposures were excluded. Patients were identified by reviewing all medical records of those who had an HIV test submitted through the Microbiology laboratory. The study was approved by The Hospital for Sick Children (HSC)’s Research Ethics Board.

A standard data collection form was used to collect the following: patient demographics; type, date and time and geographic location of exposure; presence of blood on the device, body site of exposure, occurrence of bleeding, circumstances surrounding exposure, time of hospital/clinic visit, HIV-PEP, HBV vaccination and hepatitis B immunoglobulin [HBIG] administration; adverse effects (AE) of antiretroviral therapy, patient’s baseline HBV vaccination status, and baseline and follow-up (6 weeks, 3 months and 6 months) serology test results for HIV, HBV and HCV.

Definitions

The degree of HIV risk of each exposure was categorized as substantial or negligible risk according to the Centers for Disease Control and Prevention (CDC) criteria (6,7). School exposure was defined as an exposure that took place in school/daycare buildings or grounds. Outdoor exposures referred to exposures that occurred in a community setting such as parks, parking lots or beaches. Domestic exposure included those that occurred either in the home or, in the case of a detached house, in its front or back yard. Exposures that took place in community clinics or hospital outpatient clinics were referred to as clinic exposures. HBV infection was defined by detection of hepatitis B surface antigen (HBsAg). Immunity to HBV was defined by an anti-hepatitis B surface antibody (anti-HBs) titer of ≥10 mIU/mL. Adequate follow-up was defined by having follow-up serologic testing at least once, 3 months or later after the exposure.

Statistical analysis

Median and interquartile ranges (IQR) were used to describe continuous variables and proportions to describe categorical variables. Statistical comparison between groups was by χ² or Fisher’s exact test, as appropriate, for categorical variables and by Kruskal–Wallis test for continuous variables. Statistical significance was set at 0.05.

RESULTS

Of 1492 children who had an HIV test, 66 (4.4%) met the eligibility criteria. Their median age was 6.3 years (IQR 3.8–7.8); 66.7% were male (n = 44). A source person was identified in 16.7% (n = 11) of cases, 7 of whom were HIV infected (Table 1). Six of the 7 HIV positive source persons were family members of the exposed child.

Table 1.

Exposures involving known source

Case	Age (years)	Source person	Source HIV status and clinical features	Exposure type	Risk assessment *	HIV-PEP	Outcome
1	5.0	Father	HIV+; TDF, FTC and EFV; VL < 50 copies/ mL	Cut from broken glass contaminated with father’s blood	Substantial	4 week of ZDV, 3TC and LPV/r	Completed F/U, negative
2	3.9	Grandmother	HIV+; ZDV, 3TC and EFV; VL < 50 copies/ mL	Bit grandmother†	Substantial	4 week of ZDV, 3TC and NFV	Completed F/U, negative
3	13.6	Homeless male	HIV+	Bitten by source‡	Substantial	4 week of ZDV, 3TC and NFV	Completed F/U, negative
4	1.5	Mother	HIV+; no treatment; VL 1600 copies/mL	Shared razor	Substantial	6 week of ZDV, 3TC and 4 week of NVP	Completed F/U, negative
5	5.4	Grandfather	HIV−	Shared lancet	Negligible	Not given	Completed FU negative
6	5.5	Mother	HIV+; no treatment; VL< 1000 copies/mL§	Shared toothbrush	Negligible	Not given	Completed F/U, negative
7	7.6	Sister	HIV+; TDF, FTC, EFV; VL < 50 copies/mL	Shared razor	Negligible	HIV-PEP discontinued¶	Completed F/U, negative
8	3.8	Relative	HIV−	Shared razor	Negligible	Not given	Completed F/U, negative
9	7.1	Neighbor	Unknown	Hollow-bore needle	Negligible	Not given	Completed F/U, negative
10	10.2	Classmate	Unknown	Bitten by classmate¶¶	Negligible	Not given	Completed F/U, negative
11	2.2	Brother	HIV+; ZDV, 3TC and NFV; VL < 50 copies/ mL	Put brother’s lost tooth in mouth	Negligible	Declined	Lost to follow up, unknown

ZDV zidovudine; 3TC lamivudine; FTC emtricitabine; TDF Tenofovir; EFV Efaverinz; LPV/r lopinavir/ritonavir; NFV nelfinavir; NVP nevirapine; HIV human immunodeficiency virus; HIV-PEP HIV post-exposure prophylaxis; F/U follow-up; VL viral load; cART combination antiretroviral therapy

*According to CPS and CDC criteria (5–7);

^†The grandmother had skin laceration and bleeding as a result of the bite;

^‡Bite mark on the skin of the child noted but bleeding not documented;

^§The precise VL was not available, but according to the source was <1000 copies/mL;

^¶HIV-PEP started in emergency department, but stopped by infectious diseases within 24 h after risk assessment;

^¶¶No details about the incident were documented

Table 2 shows the type of exposure and the geographic location where the exposure took place. Exposures were self-inflicted in 53% (n = 35), perpetrated by others in 22.8% (n = 15) or accidental in 21.2% (n = 14). Among children ≥6 years of age (n = 36), exposures occurred either in school settings (52.8%, n = 19) or in outdoor community settings (41.7%, n = 15). Younger children (n = 30) were most often exposed in outdoor community settings (50%, n = 15) followed by domestic (26.7%, n = 8) and healthcare settings (20%, n = 6). All six healthcare associated exposures involved young children (median age 2.2 years; range 1.3–4.2); five of these were needlestick injuries caused by inserting hands into unsecured sharps containers, and one was due to a child placing a blood stained needle cap into his mouth.

Table 2.

Location and type of exposures according to age

	≥6 years (n = 36)	<6 years (n = 30)
Location of exposures
School/daycare	19 (52.8%)	1 (3.3%)
Community	15 (41.7%)	15 (50%)
Home	2 (5.5%)	8 (26.7%)
Clinics/hospital outpatient	0 (0%)	6 (20%)
Types of exposures
Needles/lancets	29 (80.4%)	18 (60%)
Bites	2 (5.6%)	3 (10%)
Razors	1 (2.8%)	3 (10%)
Used condoms	2 (5.6%)	1 (3.3%)
Blood	1 (2.8%)	1 (3.3%)
Tampon	1 (2.8%)	0
Other*	0	4 (13.3%)

*Potentially contaminated objects placed in mouth in three children—needle cap that contained blood in an outpatient setting (n = 1), lost tooth of HIV positive sibling (n = 1), use of toothbrush of an HIV positive mother (n = 1); the forth case involved a mouth-to-mouth kiss by a stranger on the street (n = 1)

Baseline serology results for HIV, HBV and HCV were available for 64, 61 and 60 patients, respectively. Two patients had no baseline serology results available for any of the three pathogens, one due to the patient not seeking medical attention in the acute phase, the other due to the patient medical record being incomplete. In addition, baseline HBV testing was not done in two children due to documented negative HBsAg source status (n = 1), and not available in the medical record because testing was performed at an outside institution before referral (n = 1). Regarding HCV, four children did not have baseline serology performed due to documented negative HCV source status.

Antiretroviral medications were prescribed to 33.3% (n = 22) of children, four of whom were considered to be at substantial/high risk according to CDC and CPS criteria (Table 2 and Figure 1) (5–7). Before 2005, all prescriptions consisted of dual nucleoside analogue (NRTI) therapy (n = 7), whereas triple combination antiretroviral therapy (cART) predominated afterwards (92.9%; n = 14). Two children prescribed HIV-PEP despite being deemed at negligible risk were lost to follow-up; one did not fill the prescription, the other did, but failed to attend the Infectious Diseases Clinic appointment. In one child HIV-PEP was stopped within 24 h of initiation by the Infectious Diseases service, based on an assessment of negligible risk. Of the 19 patients who took HIV-PEP and for whom follow-up information was available, 63.2% (n = 12) received triple cART, and 36.8% (n = 7) received dual NRTI. HIV-PEP regimens included zidovudine, lamivudine and lopinavir/r in 45.5% (n = 10), zidovudine, lamivudine and nelfinavir in 14.3% (n = 3), zidovudine, lamivudine and nevirapine in 4.7% (n = 1) and zidovudine and lamivudine in 38.1% (n = 8).

Figure 1.

HIV exposure risk, HIV-PEP and adverse events (AE). AE reported: vomiting (n = 5); rash (n = 3); nausea (n = 2); abdominal pain and diarrhea (n = 1). §Reasons for starting HIV PEP included severity of the injury/significant blood exposure and a high degree of patient or parent anxiety. Prescribed antiretroviral therapy: ZDV, 3TC and LPV/r (n = 10); ZDV and 3TC (n = 8); ZDV, 3TC and NFV (n = 3); ZDV, 3TC and NVP (n = 1).

Fifteen of the 19 (78.9%) who initiated HIV-PEP completed the recommended treatment course, including all four classified as at substantial risk (Figure 1). Eleven of the 19 (57.9%) developed symptoms potentially attributable to antiretroviral medications, including vomiting (25%; n = 5); skin rash (15%; n = 3), headache (10%; n = 2), nausea without vomiting (10%; n = 2), dizziness (5%; n = 1) and abdominal pain with diarrhea (5%; n = 1). Of the 11 patients who had treatment related adverse effects, 8 (72.7%) were receiving triple cART, and 3 (27.3%) were receiving dual NRTI therapy. Treatment discontinuation (n = 4) or modification (n = 4) due to adverse effects occurred in eight children, all recipients of triple cART (P = 0.007, Fischer exact test; compared to dual NRTI treated subjects). Seven of these eight children were receiving protease inhibitor-based cART.

HBV vaccine and HBIG were administered to 68% (n = 45) and HBV vaccine alone to 9% (n = 6) of children at initial assessment in the Emergency Department (Figure 2). Reasons for not administering HBV vaccine or HBIG included prior vaccination (n = 10), documented negative HBsAg in the source patient (n = 3), not offered at first encounter (n = 1) and parental refusal (n = 1). Only 41.2% (21 of 51) of previously unvaccinated children were documented to have received all three doses of the HBV vaccine series.

Figure 2.

Baseline hepatitis B immune status and post-exposure prophylaxis. *Source hepatitis B surface antigen negative (n = 2), parents refused vaccination (n = 1), previously immunized (n = 1). **Source hepatitis B surface antigen negative (n = 1), not offered (n = 1), previously immunized (n = 1). §Unsure of vaccination status at first visit. anti-HBs Anti-hepatitis B surface antibody; HBIG Hepatitis B immunoglobulin; HBV Hepatitis B virus.

Fifty (75.8%) children had at least one follow-up appointment with serologic testing in the Infectious Diseases Clinic. HIV serology was performed in 63.1% (n = 41) 6-week post-exposure and in 60% (n = 39) 3–6 months post-exposure. For HBV and HCV follow-up serology was performed in 54.5% (n = 31) and 58.6% (n = 34) at 6 weeks and in 50% (n = 33) and 56% (n = 37) at 3–6 months post-exposure, respectively. None of the 40 children who completed follow-up were infected with a BBP. Of the seven children whose exposure involved a known HIV-infected source, six completed the recommended follow-up; the one child that did not was considered at negligible risk at initial assessment (Table 2).

Twenty-six children were considered to have not had adequate follow-up at Sick Kids. Reasonable explanations were evident for seven, including expressed parental preference to complete follow-up with their primary care provider (n = 5), a visitor to Canada who returned home soon after the incident (n = 1), and exposure to a family member who was documented to be seronegative to HIV, HBV and HCV (n = 1). For the remaining 19, no explanation for the incomplete follow-up was evident in the medical record.

DISCUSSION

Community-associated exposures to discarded needles or other objects potentially contaminated with BBP cause significant anxiety to parents and children and put healthcare providers in a difficult decision-making dilemma. This is exemplified by the observation that of 21 (32%) children prescribed HIV-PEP in our cohort, only 4 (19%) met criteria for being at substantial risk and therefore appropriately prescribed HIV-PEP (5–7). This apparent over-prescribing of HIV-PEP is likely in part related to uncertainties surrounding the exposure and in part to the difficulty in allaying parental anxiety regarding HIV transmission risk. In general, HIV-PEP is only indicated for exposures that pose a substantial risk of HIV transmission, such as those following percutaneous injury or exposure of non-intact skin or mucosa to blood or another body fluid visibly contaminated with blood from a known HIV positive source. In addition, HIV-PEP is only warranted if initiated with 72 h of the exposure (7).

Reported rates of completion of HIV-PEP following percutaneous exposure to discarded needles in the community varies widely from 24% to 94% (8–12). Not surprisingly, treatment discontinuation was most often related to medication adverse events. In our cohort, protease inhibitor-based cART was particularly poorly tolerated with 64% (7/11) either stopping it early or requiring a change in treatment regimen. It was noteworthy, however, that all four patients who were classified as at substantial risk of HIV infection, including two who had adverse events related to medication completed the full course of triple cART HIV-PEP. Primarily due to safety and tolerability concerns, the choice of agents used for HIV-PEP has changed over time. The current Centers for Disease Control and Prevention (CDC) guidelines recommend a 28-day course of triple cART with a preferred regimen of tenofovir, emtricitabine and either raltegravir for children 2–12 years of age or dolutegravir for children 13 years of age or older (7).

Consistent with prior literature, none of the children in our cohort were shown to have become infected with a BBP. In a systematic review of 16 prospective or retrospective observational cohort studies that included 1565 community associated needlestick exposures, only one case of BBP transmission (HBV) was documented (8). Five additional case reports of HBV (n = 2) or HCV (n = 3) transmission have been described following CA-NSI (13–16). In all five of these latter cases, alternate routes of infection could not be excluded. The one paediatric case involved a 4-year-old boy who became infected with HBV following percutaneous injury from a needle discarded by an HIV and HBV co-infected adult. None of the three who became infected with HBV (including the aforementioned child) received HBV vaccine or HBIG in the immediate post-exposure period (13).

To our knowledge, there have been no cases of documented HIV transmission following percutaneous injury from discarded needles or exposure to other objects potentially contaminated with BBP in the community setting. This is likely due to multiple factors including the overall low prevalence of HIV, the small gauge and small volume of most discarded syringes, and the inability of HIV to survive for prolonged periods in the environment (17–19). It has been demonstrated that HIV survival in syringes is shortened with smaller blood volume in the syringe and at warmer temperatures (20,21). Thus, in an experimental setting involving small volume syringes (2 μL of blood), HIV was shown to remain viable for up to 42 days at 4.0°C, 21 days at room temperature (20°C) and 7 days at higher temperatures (27°C to 37°C) (20,21).

About 90% of exposures in our cohort involved children less than 12 years of age (grade 7) when routine HBV vaccination takes place in Ontario (22). Revising the HBV vaccine to early infancy, as practiced in most parts of the world, would, therefore, eliminate the need for urgent HBIG and HBV vaccine administration as well as the need for follow-up HBV testing for most exposures. Currently, the only provinces and territories that routinely initiate HBV vaccination at birth or 2 months of age are British Columbia, the Yukon, Northwest Territories, Nunavut, New Brunswick, Prince Edward Island and Quebec (23).

The most significant limitations of this study were the small number of cases and the relatively high rate of loss to follow-up and therefore incomplete data on final HIV, HBV and HCV status and hepatitis B vaccination completion status. Some, but not all, losses to follow-up were due to stated parental preference to complete follow-up with their primary care provider. In addition, it is probable that any child tested in the community and found to be infected would have been referred back to our institution as it is the only tertiary paediatric centre in the greater Toronto area. The relatively high proportion of children exposed to a known HIV-positive source was likely reflective of Sick Kids being the only paediatric HIV care centre in the greater Toronto area and the higher likelihood of medical care being sought for an exposure involving a known HIV-positive source. Key strengths of our study, in contrast to previous literature, were the inclusion of the varied types of potential BBP exposures that led to medical care being sought, and the relatively high number of exposures that involved a known HIV-positive source.

The findings of this study suggest the need for enhanced prevention efforts. Public Health educational interventions about the potential risks associated with discarded needles that target students, school staff and parents could reduce exposure risk. Syringe exchange programs could minimize the prevalence of discarded needles that contain blood potentially contaminated with BBP. In a clinic setting, sharps containers need to be secure and out of reach of young children. The public health risk from community-based percutaneous or mucosal exposures to objects potentially contaminated with HBV is one of many factors that should be taken into account in determining the age of routine HBV vaccination.