This retrospective observational study of 81 patients revealed that the cases confirmed UVK during the 37-days COVID-19 crucial period in 2020 in Guangzhou was threefold higher (n = 61 patients) than the number during the control group in 2019 (n = 20 patients). All of the UVK cases who recorded injury photosources were injury by UV lamps during the crucial period in 2020, while by UV lamps (61.54%) or welding (38.46%) in the control group. There were more than 70% of UVK cases injured at home by household UV lamps during the crucial period in 2020, while were 15.38% in control group. They are significant differences in UVK photosource and exposure location between periods in 2019 and 2020 (P < 0.001).
Even the number of UVK cases increased so much during 2020 period, we found no cases related to welding arc or hospital-visiting UV lamp exposed, while misuse of household UV disinfection lamps account for all recorded injury photosource cases. In contrast, greater proportions of cases in 2019 were related to welding arc and medical UV disinfection lamp exposure. We suspect that the COVID-19 has had a serious impact on people's daily habits. With much of the industry shut down, people grounding themselves at homes, and taking more emphasis placed on home disinfection than ever. Consumer-grade ultraviolet (UV) disinfection lamps are chosen for SARS-CoV-2 eradication because of easy installing and using. As a result, it increased household UV lamp related UVK cases.
COVID-19 has spread across the globe, and while there are intensive efforts to reduce spread and identify treatments. Home disinfection may help prevent spread within families, but there are no guidelines on the most suitable disinfection agents and their use. A large number of Chinese citizens purchased UV lamps through the internet for daily household disinfection during the early stages of the pandemic. However, lack of relevant knowledge regarding safe use and suitable eye protection can lead to UVK. A similar phenomenon was also reported during the 2003 SARS pandemic, as GH Zhou et al found that exposure to household UV disinfection lamps accounted for 91% of all UVK cases. Ultraviolet light exposure is a major environmental danger. Natural sunlight in mountainous, snowy, or water environments is considered a major source of acute UV radiation, while major artificial sources include medical air disinfectors, tanning beds, welding arcs, photo floodlights, electrical sparks, and halogen desk lamps[10, 11]. In contrast, household disinfection lamps are not considered a major contributor. However, the risk has increased markedly in China due to the more frequent use of UV disinfection lamps.
The reasons for increased UV exposure from disinfection lamps and resulting UVK incidence can be summarized as follows. First, many users are unaware that direct eye exposure should be avoided as they have not read the safety instructions carefully. Further, most large e-commerce websites that sell household UV lamps present these warnings inconspicuously. Second, many users did not know that the UV lamp was turned on even when aware of the safety precautions, so a conspicuous warning signaling that the instrument is on should be placed on the device. We suggest that clinicians initiate public information campaigns on the dangers of UV lamp exposure.
Ultraviolet irradiation at 207 nm induces little cellular damage when used for air disinfection, while longer wavelengths can induce DNA damage, UVK, radiation cataract, dermatitis, skin cancer, and mucosal or choroidal melanoma among other diseases. However, the wavelength standard of UV disinfection lamps is 254 nm, so improper use may lead to these aforementioned complications depending on exposure level.
There are currently no consensus guidelines on household cleaning for SARS-CoV-2. A recent study in Wuhan, China, found that SARS-CoV-2 was widely distributed in the air and on object surfaces in both the intensive care unit (ICU) and a general ward (GW) during the epidemic. Since some ICU patients require airway opening, the exposure risk is even greater than in the GW, even if there is a ventilation system. These findings indicate that virus-laden aerosols concentrate near and downstream from the patient and that SARS-CoV-2 may transmit up to 4 m. A recent study in Italy also found that SARS-CoV-2 RNA can attach to outdoor particulate matter in pandemic areas, thus enhancing the persistence of SARS-CoV-2 in the atmosphere.
Otherwise, a recent study in Singapore did not detect viral RNA in air samples from isolation wards with mild COVID-19 cases before disinfection, but did detect viral RNA in vents, on floors, window sills, light switches, stethoscopes, tables, and chairs, and both inside and outside sinks. In wards with patients showing intermediate levels of infection, no viral RNA could be detected in air samples and surface swabs after wiping with chlorine-containing disinfectants, even in the absence of UV lamp disinfection. This state may be attributed to the following conditions of isolation wards: ① Patients have non-open airways by tracheal intubation, ② There are effective ventilation systems, ③ Patients are isolated in individual rooms and wear medical masks. Therefore, to avoid viruses being transmitted from droplets and close contact, more attention should be shifted to surface disinfection and hand hygiene (hand washing) rather than UV air disinfection. Moreover, if there are no potential risks of respiratory infection at home, UV disinfection may be unnecessary. In addition, the presence of virus in toilet and sink swabs suggests the possibility of fecal–oral transmission, against underscoring the value of hand hygiene for personal protection. During home quarantine, correct hand washing is still the most important measure rather than whether the hand sanitizer/soap is antibacterial[18, 19].
As indicated above, people should avoid exposure of eyes and skin to UV rays while using inexpensive and effective UV disinfection lamps in pandemic regions. We hope that these results and recommendations will encourage public health organizations to establish effective and safe disinfection protocols and promote the use of suitable personal protection during home quarantine.