Английский случай

[chuka_lis]

Вспышка ковида среди сотрудников офиса в Англии. Все сотрудники- привитые (с начала  мая до конца июля, 2 дозы, в основном- АстраЗенека).  Офисные места ограничены прозрачными щитками,  и в приницпе, сотрудники- натренированные на соблюдение противоэпидемических мер (тестироваться, самоизолироваться, этс) . Помещение проветривалось естественным путем, через окна, и вроде согласно стандартам- углекислого газа как маркера было не более 700 чнм (если 1200, то считается что проветривают плохо, ну а они, вроде нормально проветривали).
За 2 недели до вспышки в стране сняли ограничения для привитых (маски, социальные дистанции, этс). И вот в конце августа- понеслось. В среднем заболело 55% сотрудников (22 из 40). Примерно за 2 недели. Офис закрыли на время и продезинфицировали.  Среди конкретно офисных работников заболели 47%, среди секьюрити- 67%, среди уборщиков- 75%.   Каждый сотрудник встречался с клиентами лицом к лицу раз 15 в день, а секьюрити раз в полчаса  обходили офис, кроме того что записывали визитеров. Ну, уборщики каждый день убирали после работы.
Образцы, взятые с поверхностей, примерно в 17% показали наличие вируса. Рабочие места были "не личные", часть вещей- "общая". После того, как вспышку обнаружили и "придавили" местным шатдауном,  и после того, как сотрудники вернулись в офис, только в 2% поверхностых образцов определялся коронавирус  с очень низким количеством (количество циклов ПЦР более 36) частиц. Впрочем, авторы не думают, что причиной заражения послужили фомиты. Они склоняются к мысли, что то, что привитые люди перестали соблюдать другие меры предосторожности, проинициировало вспышку (ну, кроме того что пришла дельта). И еще, уж очень много было народу в небольшом помещении, да и маски перестали быть обязательными...
Часть сотрудников  (12) согласилась поучаствовать в исследованиях (тесты) и опросах, для выяснения, почему же случилась вспышка. Особой разницы в поведении не обнаружено, ну, может те кто не заболел (7), чуть больше были в маске, и привились чуть позже.
Те кто болел- все были симптоматичные,  и у всех обнаружились антитела к Н-белку. Те кто не заболел, т к привитые- были антитела только  к шипику.
Авторы думают, что, хотя вакцина защищает от тяжелой болезни и смерти, все же, для предотвращения эпидемии, должна использоватсья многоуровневая защита от передачи вируса, в соотвествии с текущими обстоятельствами и конкретными условиями.

The 40 workers included four (10.0%) cleaners, 30 (75.0%) office-based staff who had up to 15 face-to-face meetings with visitors per day, and six (15.0%) security staff who patrolled the facility on 30-minute rotating shifts, booked-in visitors, and operated shared equipment in a 7.8m2 office. The overall attack rate of SARS-CoV-2 was 55%, with 75% of cleaners (3/4), 47% of office staff (14/30), and 67% of security staff (4/6) testing positive. Between end of August and mid-September 2021, a ‘circuit break’ closure was implemented to stop transmission within the workplace. The workplace had a site specific COVID-19 prevention strategy in place based on a generic template provided by the parent organisation. Control measures included COVID-19 training for workers, single occupancy desks with 2m spacing, plastic dividers between workers and the public, commercial hand sanitizers, and a cleaning regimen including in between appointments with members of the public. Ventilation on site was predominately natural (i.e. manually opened windows) with some locally controlled air conditioning units and limited forced mechanical general ventilation. Following notification, a comprehensive investigation b 56 y the COVID-19 Outbreak Investigation to Understand Transmission (COVID-OUT) study team, part of the PROTECT COVID-19 National Core Study on transmission and environment [1], was conducted in September and October 2021 Out of 60 surfaces tested in the first round of sampling approximately 1-week after the first identified case, 10 (16.7%) were confirmed positives, and one (1.7%) was a suspected positive (Table 1). Five (8.3%) positive samples produced crossing threshold (Ct) values between 32.0-34.9. The security office appeared to be a site of enhanced contamination, with six of nine (66.7%) samples from this location testing positive including three in the 32.0-34.9 Ct bracket. Based on these findings, enhanced cleaning was performed prior to the site re-opening... Repeat surface sampling performed  approximately 1-week after re-opening identified only one positive (2.4%) and one suspected positive (2.4%) sample, both near the assay’s limit of detection. Ventilation was assessed using CO2 as a proxy; concentrations were determined by spot measurements when the facility re-opened, with continuous measurements logged over the subsequent two-week period in selected locations. These indicated that, although largely by natural means, ventilation conformed with current guidance [3], including in the security office where CO2 levels did not exceed 1200ppm and typically were <700ppm. 12 workers (100% office workers on regular day shift; 75% permanent contract) consented to participate in the COVID-OUT study, which included completing online questionnaires [4], two rounds of SARS-CoV-2 antibody testing, and three rounds of self-administered nose and throat swabs for qRT-PCR testing [2]. Of the 12 participants, five (41.7%) self-reported positive SARS-CoV-2 tests during the outbreak period; COVID-OUT serological testing confirmed all five were positive for both N- and S-specific antibodies against SARS-CoV-2 and two were positive by qRT-PCR. The non-cases were positive for S- but not N- antibodies, confirming that they had been vaccinated but not previously infected (Table 2). Prior to the outbreak, all participants, including the five cases, had received two doses of COVID-19 vaccines (date range of second dose: early May to mid-July in test  positives (cases) and mid-May to late July in non-cases... All five cases were symptomatic for COVID-19 and presented with at least one of the following symptoms: fever, dry cough, productive cough, shortness of breath, and/or loss of taste or smell. In late August-September 2021, a public-facing office in England, with adherence to governmental COVID-19 control guidance and high vaccination coverage, experienced an outbreak of SARS-CoV-2 affecting 55% of the workforce. At the time of this outbreak, governmental guidance for workplaces in England prioritized policies for risk assessments, adequate ventilation, frequent cleaning, self-isolation, and communication/training; however, social distancing and face covering usage were no longer compulsory. Two weeks before the outbreak, government guidance was amended so fully vaccinated people did not need to self-isolate if they were identified as a close contact of someone with COVID-19. While vaccines remain highly effective for preventing severe COVID-19 illness and death, SARS-CoV-2 infections among fully vaccinated individuals in this outbreak are consistent with previous reports [12] and reinforce the importance of a layered SARS-CoV-2 transmission mitigation strategy prioritising ventilation and risk assessment-informed interventions, such as testing, social distancing, appropriate occupancy levels and transmission control measures (e.g. face masks), in addition to vaccination.

Comments

[juan_gandhi]

О какое хорошее (и понятное нам, простым людям) исследование.

[chuka_lis]

наглядно.