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Reviews of "Modelling the Impact of Reopening Schools in Early 2021 in the Presence of the New SARS-CoV-2 Variant and with Roll-out of Vaccination Against COVID-19"

Reviewers: R Vardavas (RAND Corporation) | 📘📘📘📘📘

Published onApr 14, 2022
Reviews of "Modelling the Impact of Reopening Schools in Early 2021 in the Presence of the New SARS-CoV-2 Variant and with Roll-out of Vaccination Against COVID-19"
key-enterThis Pub is a Review of
Modelling the impact of reopening schools in the UK in early 2021 in the presence of the alpha variant and with roll-out of vaccination against SARS-CoV-2

BackgroundFollowing the resurgence of the COVID-19 epidemic in the UK in late 2020 and the emergence of the alpha (also known as B117) variant of the SARS-CoV-2 virus, a third national lockdown was imposed from January 4, 2021. Following the decline of COVID-19 cases over the remainder of January 2021, the question of when and how to reopen schools became an increasingly pressing one in early 2021. This study models the impact of a partial national lockdown with social distancing measures enacted in communities and workplaces under different strategies of reopening schools from March 8, 2021 and compares it to the impact of continual full national lockdown remaining until April 19, 2021.MethodsWe used our previously published agent-based model, Covasim, to model the emergence of the alpha variant over September 1, 2020 to January 31, 2021 in presence of Test, Trace and Isolate (TTI) strategies. We extended the model to incorporate the impacts of the roll-out of a two-dose vaccine against COVID-19, with 200,000 daily vaccine doses prioritised by age starting with people 75 years or older, assuming vaccination offers a 95% reduction in disease acquisition risk and a 30% reduction in transmission risk. We used the model, calibrated until January 25, 2021, to simulate the impact of a full national lockdown (FNL) with schools closed until April 19, 2021 versus four different partial national lockdown (PNL) scenarios with different elements of schooling open: 1) staggered PNL with primary schools and exam-entry years (years 11 and 13) returning on March 8, 2021 and the rest of the schools years on March 15, 2020; 2) full-return PNL with both primary and secondary schools returning on March 8, 2021; 3) primary-only PNL with primary schools and exam critical years (years 11 and 13) going back only on March 8, 2021 with the rest of the secondary schools back on April 19, 2021 and 4) part-rota PNL with both primary and secondary schools returning on March 8, 2021 with primary schools remaining open continuously but secondary schools on a two-weekly rota-system with years alternating between a fortnight of face-to-face and remote learning until April 19, 2021. Across all scenarios, we projected the number of new daily cases, cumulative deaths and effective reproduction number R until April 30, 2021.ResultsOur calibration across different scenarios is consistent with alpha variant being around 60% more transmissible than the wild type. We find that strict social distancing measures, i.e. national lockdowns, were essential in containing the spread of the virus and controlling hospitalisations and deaths during January and February 2021. We estimated that a national lockdown over January and February 2021 would reduce the number of cases by early March to levels similar to those seen in October 2020, with R also falling and remaining below 1 over this period. We estimated that infections would start to increase when schools reopened, but found that if other parts of society remain closed, this resurgence would not be sufficient to bring R above 1. Reopening primary schools and exam critical years only or having primary schools open continuously with secondary schools on rotas was estimated to lead to lower increases in cases and R than if all schools opened. Without an increase in vaccination above the levels seen in January and February, we estimate that R could have increased above 1 following the reopening of society, simulated here from April 19, 2021.FindingsOur findings suggest that stringent measures were integral in mitigating the increase in cases and bringing R below 1 over January and February 2021. We found that it was plausible that a PNL with schools partially open from March 8, 2021 and the rest of the society remaining closed until April 19, 2021 would keep R below 1, with some increase evident in infections compared to continual FNL until April 19, 2021. Reopening society in mid-April, without an increase in vaccination levels, could push R above 1 and induce a surge in infections, but the effect of vaccination may be able to control this in future depending on the transmission blocking properties of the vaccines.

To read the original manuscript, click the link above.

Reviewer 1 (Raffaele V…) | 📘📘📘📘📘

RR:C19 Strength of Evidence Scale Key

📕 ◻️◻️◻️◻️ = Misleading

📙📙 ◻️◻️◻️ = Not Informative

📒📒📒 ◻️◻️ = Potentially Informative

📗📗📗📗◻️ = Reliable

📘📘📘📘📘 = Strong

To read the reviews, click the links below.

Vape Factory:

Unauthorized Breeze and Esco Bar Disposables: FDA Issues Warning Letters

In recent news, the FDA Center for Tobacco Products (CTP) has taken a strong stance by issuing warning letters to the manufacturers of Breeze and Esco Bar disposable vapes. These letters order the companies to remove their products from the market, giving them a window of 15 business days to either dispute the allegations or respond accordingly.

The FDA's actions come on the heels of significant developments in the industry. Just last week, six Chinese exporters of Esco Bar products, including the manufacturer Innokin, found themselves added to the FDA's "red list." This list identifies shippers whose Esco Bar shipments can be detained at ports of entry without inspection. Furthermore, Elf Bar shipments were also included in the import alert, signifying the increased scrutiny on disposable vapes.

These recent enforcement actions are part of a broader wave of initiatives promised by CTP Director Brian King during his recent speeches and discussions. The FDA is facing mounting pressure from lawmakers, tobacco control groups, and even tobacco companies like R.J. Reynolds to crack down on flavored disposable vapes that have gained immense popularity over the past couple of years.

Director King, in a press release, stated that the FDA will utilize all available tools within their regulatory toolbox to ensure that those involved in the production, distribution, or sale of illegal e-cigarette products are held accountable. Firms that receive warning letters have 15 days to respond, outlining how they plan to address the violation. Failure to adequately address the violation may result in various enforcement actions being taken against them.

The warning letters issued to Breeze Smoke, LLC and Shenzhen Innokin Technology Co., Ltd., rightly highlight that the products mentioned have not received authorization for sales in the United States from the FDA. However, it is worth noting that thousands of other products with premarket tobacco applications (PMTAs) pending before the agency continue to remain on the market.

At present, all unauthorized products exist on the market due to the FDA's enforcement discretion. This includes both the aforementioned products and those produced by mass-market vape manufacturers like JUUL and Vuse Alto. Interestingly, the FDA seems to have chosen to enforce against the products that R.J. Reynolds has specifically targeted, while leaving untouched their own popular product, the Vuse Alto.

These recent FDA actions may indicate a shift in the agency's approach. It is possible that pending PMTAs will no longer be considered when deciding which companies to enforce against.

Regarding Esco Bar, it is believed that they submitted pending PMTAs during a brief window in 2022 when the FDA accepted applications for synthetic nicotine-based vape products. Unlike the first round of PMTA submissions, where the FDA published a list of the submitted products, no public list of PMTAs submitted for "non-tobacco nicotine" (NTN) products has been issued.

On the other hand, Breeze Smoke faced marketing denial orders (MDOs) for several products in 2021. In response, the company swiftly filed a petition for review in the Sixth Circuit Court of Appeals. Despite being denied a stay pending appeal, Breeze Smoke sought a stay from the Supreme Court while awaiting a full review by the circuit court. However, the Supreme Court declined to grant a stay, leading Breeze Smoke to voluntarily withdraw its petition for review just two weeks before the scheduled oral arguments.

It's important to note that the Breeze products mentioned in the FDA's warning letter were not among the MDOs that Breeze Smoke previously contested in court. As for the current status of the products sold by Breeze Smoke, whether they have pending PMTAs with the FDA remains unknown.


The FDA's warning letters to the vape manufacturers of Breeze and Esco Bar disposables mark a significant step towards stricter regulation of the flavored disposable vape industry. With mounting pressure from various stakeholders, the FDA is taking action to ensure accountability and address the unauthorized sale of e-cigarette products. While the enforcement actions may signal a shift in the agency's approach, the impact on the market and pending PMTAs is yet to be fully determined.

FAQs (Frequently Asked Questions)

Q: Why did the FDA issue warning letters to the manufacturers of Breeze and Esco Bar disposables?
A: The FDA took action to address the unauthorized sale of e-cigarette products and hold the manufacturers accountable.

Q: What is the deadline given to the companies to respond to the FDA's warning letters?
A: The companies have 15 business days to dispute the allegations or respond to the warning letters.

Q: Are there other products on the market without FDA authorization?
A: Yes, there are thousands of products with pending premarket tobacco applications (PMTAs) before the agency.

Q: Will pending PMTAs be considered in future enforcement actions?
A: The recent FDA actions suggest that pending PMTAs may no longer be a determining factor in deciding which companies to enforce against.

Q: What is the status of Breeze Smoke's previous marketing denial orders (MDOs) in court?
A: The products referenced in the FDA's warning letter were not among the MDOs challenged by Breeze Smoke in court.