Oral Hygiene Abstracts 2023

Risk factors for Long COVID in HC workers

By Emer. Prof. Laurence Walsh AO

Long COVID is an important public health issue, with an overall global estimated pooled prevalence of 43% (95% CI, 39%-46%), with a prevalence of 54% (95% CI, 44%-63%) in hospitalised patients and 34% (95% CI, 25%-46%) in non-hospitalised patients. This study determined risk factors for the development of long coronavirus disease 2019 (COVID-19) in healthcare personnel (HCP). A case-control study design was used, following an HCW who had confirmed symptomatic COVID-19 while working in a Brazilian healthcare system between March 1, 2020 and July 15, 2022. Cases were defined as those having long COVID according to the US CDC definition. Controls were defined as HCW who had documented COVID-19 infection but did not develop long COVID. In total, of 7,051 HCW diagnosed with COVID-19, some 1,933 (27.4%) developed long COVID. These were compared to 5,118 (72.6%) who had been infected but did not develop long COVID. Multiple logistic regression was used to assess the association between exposure variables and long COVID during 180 days of follow-up. Around half of the HCW with long COVID (51.8%) had experienced three or more symptoms. The most common symptoms were headache (53.4%), followed by myalgia or arthralgia (46.6%) and nasal congestion (45.1%). Factors positively associated with the development of long COVID were female gender (OR, 1.21; 95% CI, 1.05-1.39), greater age (OR, 1.01; 95% CI, 1.00-1.02) and 2 or more bouts of COVID-19 infection (OR, 1.27; 95% CI, 1.07-1.50). Long COVID was less likely to develop in those infected with the delta variant (OR, 0.30; 95% CI, 0.170.50) or with the omicron variant (OR, 0.49; 95% CI, 0.30-0.78). There was a dramatically lower likelihood of developing long COVID after receiving 4 COVID-19 vaccine doses prior to infection (OR, 0.05; 95% CI, 0.01-0.19). Overall, these results show that long COVID can be common in Health Care Workers. This is not surprising because Health Care Workers have been identified as more vulnerable to infection due to occupational exposure. Older females and those who have had >1 bout of infection are most at risk, while the maintenance of immunity via vaccination was highly protective. The identification of risk and protective factors can facilitate the development of targeted prevention strategies for individuals with elevated risk of developing long COVID.

Marra AR, et al. Risk factors for long coronavirus disease 2019 (long COVID) among healthcare personnel, Brazil, 2020–2022. Infection Control & Hospital Epidemiology (2023), 1–7. doi:10.1017/ice.2023.95

UVC devices put to the test in the real world

Ultraviolet-C (UV-C) light room-decontamination devices are not well regulated and there are no standard test protocols to demonstrate efficacy. This is an important concern because variations in test methods can markedly impact reductions of pathogens achieved by UV-C and devices may vary substantially in efficacy. It would be advantageous for healthcare facilities to have access to do-it-yourself test protocols to evaluate UV-C efficacy to compare devices being considered for purchase and to test devices intermittently to ensure appropriate performance. This study developed a do-it-yourself test protocol for UV-C room decontamination devices that would require limited or no onsite microbiological expertise. The approach used commercial Bacillus atrophaeus spores to assess the efficacy of UV-C light room-decontamination devices. B.atrophaeus is non-pathogenic with no safety concerns. The test protocol involved 10 minutes of exposure to steel disk carriers aseptically adhered to petri-dish bottoms positioned parallel to lamps 0.914 m from the device at the midpoint of the lamps. For each device, 10 disks exposed to UV-C were aseptically transferred to tubes containing 2 mL trypticase soy broth that were incubated for up to 7 days. The percentages of disks with positive cultures were calculated. Overall, 4 UV-C devices based on low pressure mercury lamps reduced B. atrophaeus by ≥3 log10 colony-forming units in 10 minutes (Tru-D, Rapid Disinfector, Guardian, UVDI-360), whereas a smaller device (Vortex-UV) required 60 minutes. For devices that have relatively low UV-C output, better results may be achieved with longer cycle times and/or by placing multiple devices in the room. Of 10 in-use devices, only 1 was ineffective. The findings provided proof of concept that this protocol could be useful for onsite evaluation of UV-C light room-decontamination devices. The proposed test method requires limited or no onsite microbiological expertise. Colorimetric indicators and irradiance measurements using a radiometer could also be useful as adjunctive methods to assess UV-C dose delivery.

Cadnum JL, Donskey CJ. A do-it-yourself test protocol using commercial Bacillus atrophaeus spores to evaluate the effectiveness of ultraviolet-C light room-decontamination devices. Infection Control & Hospital Epidemiology (2023), 1–4. doi:10.1017/ice.2023.24