Position Paper 8: Impact of Community Lockdowns

May 15, 2020

Purpose, Context and Summary: This paper examines community lockdowns as a potential option to address pandemic spread while taking into account the economic, social, and health costs of a state- or nation-wide lockdown (See appendix 2 for methodology of the models and analysis). Given that there are distinct clusters of confirmed cases among and within states (see appendix 1), there may be an opportunity to deploy smaller, community quarantines as a strategy to contain spread or delay and reduce disease peak, while mitigating the challenges of a widespread national lockdown. Community lockdowns may have negative impacts including reduced earnings, food insecurity, and accessibility of healthcare and social services, which should be taken into account. Consider taking a disaggregated geographical approach, imposition of NPIs, and

other aspects of the response (e.g. distribution of aid, testing, etc.) based on factors such as current state of the pandemic, current food security and poverty. Accompanying PowerPoint slides provide illustrations of areas where the epidemic is growing and community resilience measures that may inform choice of areas for lockdown.

Take account of specific populations and needs. See Appendix 4 for more details on strategies in high risk or vulnerable populations.

Modelled impact of community lockdowns (using multiple models – see appendices):We used agent-based modeling to examine the effects of different community quarantine strategies. Although this model has been calibrated with certain parameters relevant for the Nigerian context (e.g. age distribution of the Nigerian population, average household size, school attendance, population density, etc.) this model does not represent a projection of the actual pandemic trajectory. Rather, it demonstrates the theoretical difference in projected cases under different scenarios in this modeled virtual space. The model suggests:• While the pandemic is still in localized transmission, strategic, targeted community

lockdowns that are implemented effectively can reduce the total number of infections by ~15% compared to a strategy that only relies on individual isolation. This strategy requires a ~1.5x increase in person-isolation days compared to an individual-isolation-only strategy.

• Once the pandemic reaches widespread community transmission, community lockdowns have negligible impact on total cumulative number of infected people. If implemented effectively, community lockdowns during widespread community transmission can reduce peak number of cases and delay this peak by several weeks to months. However, achieving this delay in spread would require ~4x the number of person-isolation days (and associated wage loss, food security, etc.), compared to a strategy that does not involve community lockdowns but does use individual isolation to limit pandemic spread.

• Using representative sampling as a complement to individual testing of symptomatic cases to guide when to unlock a community (by identifying asymptomatic cases) does not meaningfully impact spread if individual testing for symptomatic cases is widely available.

• Timely and targeted deployment of community lockdowns can impact near-term mortality outcomes. SEIR modelling of Lagos City1, for example, indicates that continuing the lockdown in Lagos Mainland district until June 5 could reduce the anticipated number of cumulative deaths by up to 9% (compared to a scenario where lockdown is lifted for the whole city). This model indicates that continuing the lockdown in Lagos Mainland, Mushin, and Alimosho could reduce the

anticipated number of cumulative deaths by up to 25% by June 52. However, while the number of deaths may be reduced during this period, there is a possibility that lockdowns only delay the eventual spread of the pandemic and delay peak cases without reducing overall number of infections.

Consequently, a key deciding factors are whether there is localized or widespread community transmission, the availability of testing, and ability to provide essential services and prevent civil unrest.

1. When, where and how to deploy lockdowns (evidence from the literature and experience of other countries):

When to deploy a lockdown: There is no consensus on the ideal threshold to trigger a lockdown. However, there are generally two broad categories of measures that can be considered: epidemiological metrics (e.g. number of cases, growth rate, reproduction number) and sufficiency of health system capacity (e.g. number of beds, PPE, medical oxygen, and ventilators to meet projected demand).3 Africa CDC recommends community quarantines at phase 3 of 4 (See Appendix 3).

Criteria for reaching this phase include local outbreaks merging, deaths outside known transmission chains, multiple transmission chains, case detection of SARI4 in cases with no known exposure.

Countries have taken different approaches. India categorized districts as green, orange, or red, with increasing restrictions at each level. To move from red or orange to green, districts must have no new cases for 21 days.5 China selectively locked down high risk areas like Hubei province or areas with emerging clusters like Jilin, which has been placed under partial lockdown after a cluster of 21 new cases has emerged.6 South Africa has operated a selective lockdown process at provincial or district level with set criteria for these.7 An American think-tank suggests using a stay-at-home advisory when State case counts are doubling every 3-5 days and removal of the order when new cases declined steadily for 14 days.8

Where to deploy a lockdown: Different countries have taken different approaches to the size of area they choose to lockdown. Some countries have locked down apartment buildings or small neighborhoods while others have imposed city-wide lockdowns. Locking down at smaller levels can minimize economic and social impacts but may or may not control the pandemic depending on the nature of the outbreak. Examples include:• Residences: In China, lockdowns affected at least 760M people varying strictness

ranging (screening at entrances to full movement bans).9

• Neighborhood: India has locked down parts of Dharavi, a large informal settlement in Mumbai.10

• City: Ghana has implemented city level lockdowns on the city-level, quarantining the Greater Accra and the Greater Kumasi Areas.11

How to operationalize a lockdown: This requires a broad set of capabilities tailored to the specific needs of the geography:• Geography: Must consider difference between urban and rural areas. Highly dense

urban centres may require quarantines to disrupt local transmission, while less dense areas, may require lockdowns to prevent spread of the virus across a broader geographic area.

• Testing: Greater testing capacity can aid in determining when and where a lockdown should be imposed (as detailed in May 5 position paper)

• Enforcement is required to ensure effectiveness of lockdowns. For example, India has faced challenges in managing social unrest.12

• Delivery of essential goods / services: To minimize economic and food security impacts of lockdowns, countries can deliver essential goods / services. For example, in India, a relief package is provided to the poor including free food, cash

transfers and free gas cylinders for families for the next three months.13 However, even with relief packages in place, logistics for delivery of goods and services may be difficult.

Appendix 1. Pandemic trajectory in long-term based on two models, and maps of current cases

State % change in time spent at home before pandemic and after May 4th (end of federally mandated lockdown in certain states)14

Infections after 4 months, assuming limited social distancing in placeMedian and (80% CI)(Model A)

Infections after 4 months, assuming 20% reduction in mobility for next 90 days(Model B15)

Lagos 32%11,193,000 (4,533,000-17,641,000)

10,220,394

FCT 34% 2,846,000 (675,000-4,819,000)

2,719,512

Kano 25%10,570,000 (1,092,000-18,377,000)

9,446,766

Gombe   2,171,000

(23,000-4,071,000)

Borno 27% 4,361,000 (136,000-8,010,000)

3,966,816

Bauchi   5,574,000

(1,731,000-9,210,000)Katsina  

6,501,000 (1,848,000-10,917,000)

5,516,705

Jigawa   3,830,000 (255,000-7,413,000)

Ogun 23% 3,933,000 (316,000-6,892,000)

3,740,906

Sokoto   3,478,000

(36,000-6,721,000) 3,364,810

Osun 9%   2,895,651

Zamfara    

2,995,100 Edo 18%  

2,789,611 Kaduna 28%  

5,896,942 Delta 18%  

3,794,374 Other states**

 106,186,000 (37,963,000-177,249,000)

Total 26% 160,644,000

(48,607,000-271,320,000)

Note: Cells are left blank when modeling data not available**Estimates shown in this row include all states in Nigeria not listed in the table.

Figure 1. Map of reported cases by LGA, as of May 10, 2020. Note that reported cases is highly dependent on availability of testing and other factors.

Figure 2. Map of reported cases by LGA in Lagos, as of May 10, 2020. Note that reported cases is highly dependent on availability of testing and other factors.

Figure 3. Map of reported cases by ward in Lagos, as of May 10, 2020. Note that reported cases is highly dependent on availability of testing and other factors.

Appendix 2. Methodology of models and analysis presented

SEIR modelModel A: As described in previous position papers on April 23 and May 5, 2020, we use a modified, stochastic, Bayesian SEIR model that accounts for asymptomatic and symptomatic cases among infectious populations. This model incorporates case data from the NCDC as of May 11, 2020. The model reflects differential expected effectiveness for each NPI in the Nigerian context.

Model B: We used an age-stratified compartmental SEIR model to estimate the number of cases, deaths and demands on healthcare for a range of scenarios for all states in Nigeria currently reporting deaths on more than 3 dates. This model is an extension of that used in a recent released report (https://www.imperial.ac.uk/mrc-global-infectious-disease-analysis/covid-19/report-12-global-impact-covid-19/). The model has recently been extended to capture the impact on mortality that health capacity constraints may have. We have adapted the inputs to adjust for the healthcare capacity in each state investigated, and the expected population demographics.The underlying assumptions of infection fatality ratio (IFR), incubation period and days between onset of symptoms and death are further explained in (Verity et al., 2020) and https://mrc-ide.github.io/squire/. Model runs are calibrated to the cumulative number of deaths observed in a state.

Lagos city modeling16:

ABM model methodologyAs described in a position paper on May 5, 2020, we use an agent-based model (ABM) to estimate the impact of different lockdown strategies on pandemic spread at different points in time. An ABM models a virtual “space” where individual “agents” (i.e. people) move, become infected, and expose each other to the virus in order to model pandemic spread. Although this model has been calibrated with certain parameters relevant for the Nigerian context (e.g. age distribution of the Nigerian population, average household size, school attendance, part of active population and religious practice), this model does not represent a projection of actual pandemic trajectory in Nigeria or any other country. Rather, it demonstrates the theoretical difference in projected cases under different scenarios in this modeled virtual space.

Appendix 3. Africa CDC guidance on community lockdowns

Africa CDC suggests the use of community lockdown to reduce pandemic spread in certain cases.17 Africa CDC recommends community lockdowns when the outbreak is advancing (Phase 3), but not when there is a large outbreak with nationwide transmission (Phase 4). In Phase 4, the aim is to alleviate the burden of the healthcare services, but in Phase 3, the aim is to delay and reduce the outbreak peak.

Africa CDC: Protocol for Enhanced Severe Acute Respiratory Illness and Influenza-like Illness Surveillance for COVID-19 in AfricaAfrica CDC has outlined a stepwise approach to deploy for areas within five phases of epidemic by defining each phase and the appropriate measures for each. Some of the response measures are included below:

Epidemic phase

Characteristics of the phase

Response measures

Phase 0: No COVID-19 case

No reported cases in-country

Ensure adequate preparation for COVID-19 through central coordination, surveillance, laboratory, IPC and clinical management, and communication and community mobilization

Phase 1: Early Stage on outbreak

One or more imported cases

Limited local transmission related to imported case

Prevent sustained transmission of COVID-19 by: Activate Emergency Operation Center and

response plan for COVID-19 Intensify surveillance at point of entries (PoE)

and begin contact tracing Home quarantine all close contacts Test all symptomatic cases and contacts who

develop symptoms Establish triage at all health facilities and

isolation centers within designated hospitals Phase 2: Expanding outbreak

Increasing numbers of imported cases

Increased local spread but all cases linked to known transmission chains

Outbreak clusters with a known common exposure

Contain and slow transmission of COVID-19 Intensify contact tracing and adherence to

quarantine; prioritize contact for follow-up with highest risk exposures if limited resources

Expand testing around each cluster to identify any undetected transmission chains

Implement social distancing measures and restrict mass gatherings

Strengthen support strategy for those under home quarantine

Phase 3: Advancing outbreak

Localized outbreaks start to merge

One of more deaths occur outside known transmission chains

Sustained person to person transmission—multiple generations in transmission chains

Cases are detected among SARI cases with no known exposure

Delay transmission of COVID-19 to delay and reduce outbreak peak and burden on health services Halt contact tracing in all outbreak areas; only

trace in districts in Phase 0 of epidemic Continue to test cases in other areas that may

be in Phase 1 or Phase 2 of epidemic Test all SARI cases presenting to hospital to

aid in isolation management Home isolation for mild and moderate cases

that do not require hospitalization Consider community lockdowns for areas with

exponential transmissionPhase 4: Large

Widespread sustained community

Reduce mortality among severe COVID-19 cases Halt all contact tracing with few exceptions

outbreak with nationwide transmission

transmission Multiple generation

transmission chains can be identified but most cases occurring outside of chains

Community-wide transmission throughout all or nearly the country

such as outbreaks in hospitals Aim to reduce the delay of waiting times at

hospitals to prioritize severe or critical cases Test hospital admissions for differential

diagnosis Set up additional temporary healthcare

units/facilities for COVID-19 cases Consider lifting lockdowns and closures with

caution to prevent mass exposure of non-immune population

Appendix 4: Vulnerable or high-risk populationsThe government can consider interventions for specific populations that may be especially at risk for transmission.

Healthcare workers: In addition to providing sufficient PPE to minimize transmission at work, many governments have supported additional measures to help healthcare workers self-isolate to reduce risk of transmission. For example, hotels in US, India, and UK have allowed healthcare workers to self-isolate in their vacant rooms.18

Prisons / correctional facilities: Over 22% of prison admissions in Nigeria were reported to be inmates 51 years old and above in 2016, making up the second-largest age-group for prison admissions.19 This group may require special attention as the elderly are considered more at risk for severe complications and fatality from COVID.

o Amnesty International recommends granting early and/or conditional release for older prisoners who committed minor and non-violent crimes.20

o In South Africa, the president announced to release over 19,000 low-risk inmates (e.g., passed their minimum detention period or will approach the period within the next five years) from correctional facilities to prevent COVID-19 outbreak. Similar measures in Nigeria are being discussed.21

IDPs: There are over 2 million internally displaced individuals (IDP) in northeast region of Nigeria, many of whom were already facing food insecurity prior to the pandemic.22 Strategies considered by other governments to protect IDPs include:

o Kenya: The Kenyan government has banned entry in and out of two formal camps with populations over ~200,000, and host communities to reduce pandemic spread. COVID-19 cases have not been reported yet in those two formal camps. UNHCR plans to distribute two months’ food rations at once within the camps.23

o Bangladesh: Local NGOs have restricted the number of aid workers allowed into and out of the camps. Of the aid workers allowed, much of their work involves training community leaders to educate the Rohingya refugee camps population on accurate COVID-19 information.24

o Greece: NGOs such as Doctors without Borders are prioritizing additional water and sanitation facilities within refugee camps in Greece.25

Almajiris: The magnitude of the proposed relocation of Almajiris may impose operational constraints and will require precautions to prevent further spread due to the relocation. Examples of other countries managing similar movement of large groups amidst a pandemic include:

o Ethiopia: Saudi Arabia has deported over 3000 Ethiopian migrants to Ethiopia since the start of pandemic and has plans to deport over 200,000 migrants. Ethiopian MoH requires all migrants to be tested and quarantined for a minimum of 14 days in local schools and universities that have been closed due to pandemic.26

The analysis in this paper is purely the work of the Nigeria COVID-19 evidence synthesis group* for use by the PTF. Unauthorized use or publication of this material without the permission of the PTF is prohibited.

* The Nigeria COVID-19 evidence synthesis group is chaired by Prof Ibrahim Abubakar, scientific and technical advisor to the PTF. 

References

1 Lara Gosce, et al. “COVID-19 Modelling in Lagos City”, UCL2 Baseline scenario: No lockdown, 85% of symptomatic cases are notified, no contact tracing. Lara Gosce, et al. “COVID-19 Modelling in Lagos City”, UCL3 Racha Fadlallah and Fadi El-Jardali, “K2P COVID-19 Series: Exiting the COVID-19 Lockdown: A Road Map for Action,” Knowledge to Policy (K2P) Center, Beiruit, Lebanon, April 20, 2020, https://www.aub.edu.lb/k2p/Documents/K2P%20COVID_19%20Series_Exiting%20the%20COVID-19%20Lockdown_A%20Road%20Map%20for%20Action_April%2021_2020__.pdf#search=lockdown4 Severe Acute Respiratory Infection5 “Covid-19: Centre lists red, green zone distrcits for week after May 3,” Times of India May 2, 2020; “Full list of Red, Yellow, Green Zone districts for Lockdown 3.0,” India Today, May 1 20206 Zhuang Pinghui, "China’s Jilin city goes into partial lockdown to contain coronavirus cluster,” South China Morning Post, May 13, 2020, https://www.scmp.com/news/china/society/article/3084203/chinas-jilin-city-goes-partial-lockdown-contain-coronavirus; BBC News, “Coronavirus: People of Wuhan allowed to leave after lockdown,” April 8, 2020, bbc.com/news/world-asia-china-52207776.7 https://za.usembassy.gov/health%E2%80%AFalert-lockdown-updates-u-s-embassy-pretoria-south-africa-april-24-2020/8 Scott Gottlieb, Caitlin Rivers, Mark B. McClellan, Lauren Silvis, Crystal Watson, “National Coronavirus Response: A road map to reopening,” American Enterprise Institute, March 28, 2020, https://www.aei.org/wp-content/uploads/2020/03/National-Coronavirus-Response-a-Road-Map-to-Recovering-2.pdf9 Raymond Zhong and Paul Mozur, “To Tame Coronavirus, Mao-Style Social Control Blankets China,” New York Times, February 15, 2020, https://www.nytimes.com/2020/02/15/business/china-coronavirus-lockdown.html10 Soutik Biswas, “Coronavirus: the race to stop the virus spread in Asia’s ‘biggest slum,’ BBC, April 6, 2020, https://www.bbc.com/news/world-asia-india-5215998611 The Presidency, Republic of Ghana, “Address to the Nation by President Akufo-Addo on Updates to Ghana’s Enhanced Response to the Coronavirus Pandemic,” March 27, 2020, http://presidency.gov.gh/index.php/briefing-room/speeches/1545-address-to-the-nation-by-president-of-the-republic-nana-addo-dankwa-akufo-addo-on-updates-to-ghana-s-enhanced-response-to-the-coronavirus-pandemic-on-friday-27th-march-202012 “Coronavirus spreads among Indian police enforcing world’s largest lockdown,” Reuters, 5/6/202013 Kunal Purohit, “India COVID-19 Lockdown Means No Food or Work for Rural Poor,” Aljazeera, April 2, 2020, https://www.aljazeera.com/news/2020/04/india-covid-19-lockdown-means-food-work-rural-poor-200402052048439.html14 Based on Google Community Report mobility data published 5/12/2020. Percent change indicates the difference between the average time spent at home over the four most recent days of data compared to prior to the lockdown. Blanks indicate that data was not available.15 As shown in 20% reduction for 90 days scenario in Arran Hamlet, et al., “Modelling the spread of COVID-19 in Nigeria: Simulating increased unreported deaths in Kano state,” On behalf of COVID-19 Modelling response team, MRC Centre for Global Infectious Disease Analysis, Imperial College London. 16 Lara Gosce, et al. “COVID-19 Modelling in Lagos City”, UCL17 “Protocol for Enhanced Severe Acute Respiratory Illness Influenza-Like Illness Surveillance for COVID-19 in Africa,” Africa CDC, 4/9/202018 “Hotels opens as ‘comforting refuge’ for health care workers,” New York Times, 4/16/2020; “Taj hotels in Mumbai to host doctors, nurses on COVID-19 duty,” The Times of India, 4/4/202019 “Prison Admissions by Age Group (2013-2016),” National Bureau of Statistics, 2016 20 “Protect detainees against COVID-19,” Amnesty International, 202021 “COVID-19: South Africa grants parole to 19,000 inmates,” Anadolu Agency, 5/8/2020; “Buhari asks Nigeria’s chief judge to free prisoners because of coronavirus,” Reuters, 4/21/202022 “Displacement Tracking Matrix Nigeria, IOM UN Migration, 8/201923 “Kenya bans entry to two refugee camps hosting 400,000 people,” Aljazeera, 4/29/202024 “Distancing is impossible: refugee camps race to avert coronavirus catastrophe,” Nature, 4/24/202025 Ibid. 26 “U.N. says Saudi deportations of Ethiopian migrants risks spreading of coronavirus,” Reuters, 4/13/2020