Is the environmental sample positive in Xinguan vaccination unit? Notice issued by CDC

Recently, some provinces have detected NCV nucleic acid positive in environmental samples collected and tested by NCV vaccination units, which brings confusion to vaccination and monitoring

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After analysis and judgment by experts, the following technical suggestions are put forward for related work

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1、 Nucleic acid test results and source determination of environmental samples from vaccination units the Institute of viral diseases of CDC conducted nucleic acid test on environmental samples collected from some provinces and cities of Xinguan vaccination units

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The results showed that the nucleic acid of tabletop, wall, door handle, corridor and other environmental samples from vaccination units (injection room, observation room, external corridor, etc.) were positive

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The whole genome of the new coronavirus was sequenced at the same time

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The results showed that the genome sequence of the virus in the environmental samples was consistent with that of the vaccine strain in the detected vaccine bottle, and there was significant difference in the composition of genomic variation sites between the two strains

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It was preliminarily determined that the viral nucleic acid in the vaccination environment of Xinguan vaccine came from the vaccine solution

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2、 Risk assessment of nucleic acid positive in environmental samples of vaccination units (1) analysis of the causes of nucleic acid positive and infectious risk

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The new coronavirus inactivated vaccine was prepared by culturing and inactivating wild virus

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The virus has lost its infectivity and pathogenicity, but it still retains a relatively complete viral nucleic acid fragment

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In the process of vaccination, opening the vaccine bottle, extracting the vaccine solution, exhausting the syringe, and residual liquid in the syringe or vaccine bottle after vaccination may contaminate the surface of the inoculation table, wall, door handle, corridor, inoculator and recipient clothing in the form of liquid or aerosol

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Because of the high sensitivity of polymerase chain reaction (PCR), if the nucleic acid fragments are sampled before degradation, the nucleic acid detection results are likely to be positive

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Because the virus nucleic acid in the inactivated vaccine has no activity, it is not infectious

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(2) Objective to analyze the risk of DNA contamination in the environment of vaccination unit

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In the process of inoculation, the aerosol containing virus nucleic acid or vaccine residual liquid may pollute the desktop, ground, staff, recipients and their personal belongings of the inoculation room, and may spread to a long distance, causing nucleic acid pollution in the injection room, observation room, external corridor, other departments near the vaccination clinic, toilet and so on

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The scope of nucleic acid contamination may be affected by the number of vaccinated people, the number of staff, the mode of activities, and the air circulation

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(3) The risk of nucleic acid test positive for staff due to environmental exposure

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In the process of vaccination, the vaccine solution may contaminate the surface of workers’ clothing, gloves or their personal belongings, resulting in positive nucleic acid detection at the contaminated place

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In some provinces, the nucleic acid of the vaccine strain was positive in the environment of the vaccination unit, while the nucleic acid of the nasopharyngeal swab carried out by the staff was negative

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Although there is no positive report of nasopharyngeal swab nucleic acid test caused by aerosol inhalation of vaccine solution, it still needs attention and research evaluation

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3、 Suggestions (1) suggestions on monitoring environmental samples of vaccination units

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In view of the fact that the vaccination work of each vaccination unit will continue for a period of time, the risk of vaccination site contaminated by vaccine nucleic acid is high, and routine monitoring of the vaccination environment will interfere with the early warning of epidemic situation monitoring, so it is not recommended to carry out routine environmental sample collection and nucleic acid detection for the vaccination unit

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If the surveillance has been carried out and the virus nucleic acid is positive, or the environmental samples collected near the vaccination site are positive, it is recommended to determine whether the nucleic acid is a vaccine strain by virus genome sequencing

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If there is a local outbreak of COVID-19, and epidemiological information suggests that the epidemic is related to the staff or recipient of the vaccination unit, the specific vaccination units can be sampled according to the actual situation and combined with epidemiological information and the sequencing results of the viral genome

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(2) Suggestions on the implementation of vaccination organization and environmental disinfection

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The first is to reduce the number of accompanying personnel of the recipients, do a good job in the health screening of the recipients and accompanying personnel, and require them to wear masks according to the regulations when they enter the vaccination unit for health inquiry and temperature detection

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Second, according to the requirements of the joint prevention and control mechanism on the vaccination of novel coronavirus vaccine for key groups, and in accordance with the principle that all kinds should be used, the vaccination of novel coronavirus vaccine for the staff of the vaccination unit should be completed

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Three, vaccination staff should take corresponding protective measures, wearing masks, wearing isolation clothes, wearing work caps and gloves

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After the vaccination is finished, the personal protection will be removed and treated as a medical waste

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Disinfection should be carried out before inoculating or using hand sanitized disinfectant

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Replace the new respirator when leaving the room, do not bring personal belongings into the vaccination room, and comply with the local COVID-19 defense

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Control regulations

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Fourth, keep the environment clean, strengthen ventilation, and do a good job in routine cleaning and disinfection according to the specifications

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When the nucleic acid of the vaccine strain was positive in the environmental samples, there was no need to take additional large-scale killing measures

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Fifthly, strengthen the management of medical waste in Xinguan vaccination units, use double-layer garbage bags to pack and seal tightly, so as to avoid the vaccine nucleic acid from polluting the environment outside the vaccination units through medical waste

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China Center for Disease Control and prevention January 22, 2021 source: China Center for Disease Control and prevention understands the global times three views, please pay attention to our or below the two-dimensional code, and click on the top of the article, click the global times (WeChat official account ID:hqsbwx).

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