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Approaches to Combatting the COVID-19 Pandemic

Bar diagram on deaths from COVID-19 and other global challenges.

In this live document, we look at points where the COVID-19 pandemic can be successfully tackled, such as prevention of transmission, vaccination, interconnections with other topics as well as useful scenarios and strategies, and also the relative importance that should be given to addressing COVID-19 in comparison to other global challenges. Understanding this will enable better prioritization of efforts in tackling COVID-19 and will also indicate the most effective strategies to combat the pandemic.




How Much Priority Should we Assign to Fighting COVID-19?


Findings and Recommendations


There are infectious diseases that are both more or less contagious and more or less fatal than COVID-19. However, what makes COVID-19 so dangerous is that it is a newly emerged viral disease for which there was no existing immunity in humans. COVID-19 could rapidly infect the majority of the global population, much more than any other infectious disease. A worst-case scenario suggested that, without any countermeasures, 90% of the world population could have got infected (1).

Sources, Details and Definitions


(1) Walker et al.                                                                                          

Such development occurs quickly, with one infected person transmitting to others at an average speed of 4-8 days (1).

(1) Park et al.                                                                                          

Further uncertainty and risk are posed by the fact that emerging diseases can have higher mutation rates, which can lead to more or less harmful strains. This is the case with variants that crowd out older strains, such as the variants Alpha to Omicron, which is thought to be possibly four times more contagious and to require an additional vaccination dose (1). The mutations even go so far that the recovered have little natural immunity from infection with an older strain of the virus and the effectiveness of vaccines decreases with each major variant (1).

(1) On the Alpha variant (B.1.1.7, first observed in the UK, approximately 71% more contagious than the previous strain): PHE, p. 10; ECDC. On the Beta variant (B.1.351, first detected in South Africa): Abdool Karim; WHO. On the Gamma variant (P.1, emerged in Brazil): Faria et al. 2021. On the Delta variant (B.1.617.2, first observed in India): CDC 2021. On the Omicron variant (B.1.1.529, emerged in Southern Africa): WHO 2021, Andrews et al. 2021, ECDC 2021 (on vaccines and previous infection), Ferguson et al. 2021, HKU Med 2021, Lu et al. 2021, Burki 2021 (replication rate of the original strain of SARS-CoV-2: 2.5, the delta variant: just under 7, the omicron variant: possibly 10), Liu et al. 2021.

COVID-19 kills by the millions. The pandemic caused 1.78-1.80 million confirmed deaths globally in 2020 (1). By the end of 2021, this number has grown to 5.41-5.45 million (2). By April 2022, it is projected to increase to 6.59 million, even with the current countermeasures and vaccination plans (3). Including unreported cases, the global death toll is estimated at 12.6 million by the end of 2021 and projected to rise to 13.9 million by April 2022 (4). Another estimate of total deaths - confirmed and unreported - includes as many as 18.6 million at the end of 2021 (5).

(1) WHO, JHU, as of 30 Dec 2020.

(2) WHO 2021 (5.41 million), JHU 2021 (5.43 million), Worldometer 2021 (5.45 million), as of 31 Dec 2021.

(3) IHME 2021 (projection of reported deaths, uncertainty interval 6.27-7.00 million, starting from a modeled 5.89 million confirmed cases at the end of 2021, uncertainty interval 5.85-5.91 million)

(4) IHME 2021 (total deaths, uncertainty interval 9.00-18.3 or 10.0-20.3 million, respectively).

(5) The Economist 2021 (95% confidence interval 11.7-21.7 million).                                                         


Projected Global COVID-19 Deaths by April 2022

  Diagram on projected COVID-19 deaths by April 2022.

Source: IHME 2021 (update every two weeks).


These figures include undiagnosed cases but not the aggravating impact of COVID-19 on other health issues. Anyway, the death toll per year surpasses by far that of any other infectious disease (including pneumonia/lower respiratory infections, tuberculosis, hepatitis, HIV/AIDS or malaria). The annual COVID-19 death toll is also higher than that of child and maternal undernourishment. It was similar to that from outdoor air pollution in 2020, which included the build-up of the pandemic, but much higher in 2021 (1). The impacts of COVID-19 exceed those of all other global problems covered by the Global2030 review, such as neonatal mortality or unsafe water (see the following diagram) (2).

(1) GBD, WHO - note that these estimates take non-registered deaths into account.

(2) Topics are included in the Global2030 review if they result from limited access to vital resources - such as food, clean air or health care - and cannot be solved by the affected individual themselves but can actually be reduced by organized human activities, such as medical intervention or governmental policy.


Reported and Total COVID-19 Deaths in 2020 and 2021
Compared to Total Deaths from Other Major Global Challenges in 2019
(in Millions)

Bar diagram on deaths from COVID-19 and other global challenges.

Sources: IHME GBD 2020, WHO GHE 2020, WHO 2021, JHU 2021, IHME 2021.


However, deaths from COVID-19 could have been much higher if strong countermeasures had not been undertaken. Worst-case scenarios, assuming no mitigation measures, indicated a multiple death toll in the tens of millions, similar to the 1918/19 influenza pandemic death toll ("Spanish flu") (1). Therefore, it is appropriate that countries treat COVID-19 as the most immediate global challenge.

The human impact of COVID-19 can be reduced not only by lockdown and containment measures, but now also - at lower societal and economic costs - through the roll out of the largest vaccination programme in human history. However, the COVID-19 vaccination programmes face obstacles as they need to be expanded globally and will need to be repeated, to an extent currently unknown.

(1) Walker et al.                                                                                          




How Does COVID-19 Transmit and How Can we Prevent Transmission?


COVID-19 can transmit from person to person via

  • respiratory droplets released through coughing, sneezing, laughing, shouting, singing or speaking (1)
  • aerosols released in the same way and additionally through breathing out, or formed by droplets shrunk through evaporation, allowing for airborne transmission of COVID-19 up to several meters, or room scale (2), probably being infective for at least three hours (3) (4)
  • and contact to lips, nose or eyes, e.g. by hands contaminated with the virus from a handshake or a surface contaminated by droplets or touch (5).

(1) ECDC; WHO, p. 1; Hamner et al.

(2) Morawska et al.
Aerosols consist of small droplets that remain suspended in the air for longer than larger droplets and can follow air flows.

(3) van Doremalen et al.

(4) Tellier et al. (terminology); Chirico et al., Lednicky et al., Santarpia et al., Bahl et al., Prather et al., Morawska et al., Asadi et al., Mittal et al., National Academy of Sciences, Liu et al., Anderson et al., Stadnytskyi et al., Li et al., Chen et al., Ma et al.

(5) ECDC.

Contamination of the following surface materials can remain infective for different time-frames:

  • paper for less than 3 hours
  • cardboard for 1 day
  • treated wood and cloth for less than 2 days
  • steel for 2-6 days and
  • plastic surfaces for 3-6 days (van Doremalen et al., Chin et al.).

These transmission paths can be prevented by

  • wearing face masks, which protect both the wearer and others against contaminated droplets and aerosols (1). There are different types of face masks available:
    • N95, FFP2 or FFP3 masks/respirators have a 92.8-99.9% efficacy, if fitted correctly, otherwise efficacy is below 70% (2).
    • surgical masks have a 75-94.5% efficacy, if fitted correctly, otherwise below 70% (3). -
      The Hong Kong general public had a face mask usage of 96.6%, and an 82.7-95.7% lower incidence rate of COVID-19 compared to major non-mask-wearing countries (4). Diagram on infections from COVID-19 in countries with or without community mask-wearing.
      Source: Chi-Chung et al. (April 2020), p. 111.
    • cloth masks have different efficacies against the COVID-19 virus, from 25 to 89%, depending on the material used. If no nose clip is integrated, the efficacy is even lower, as a leakage of 1% roughly halves the filtration capacity (5).
    • masks with a ventile only protect the wearer (6)
    • wearing eye-protection or faceshields (7) or (large) glasses (8) could prevent viral transmission via the eye
  • physical distancing, e.g. maintaining a distance of 1.5-2 metres or more (9); but this does not help in rooms filled with aerosols (10)
  • good ventilation in closed rooms (11)
  • cough hygiene by coughing into a tissue, elbow or non-reusable handkerchief (12)
  • hand hygiene by avoiding handshakes, avoiding touching handles used by others, avoiding touching ones face and regularly washing hands thoroughly with soap or disinfection solution (13)
  • applying disinfectants to contaminated surfaces (14)
  • and last but not least, reducing the frequency and duration of direct contacts with other persons, particularly those not using the above-mentioned means of prevention (15).

(1) van der Sande et al. (2008), IHME, i.a.

(2) Efficacy of N95, FFP2 or FFP3 masks/respirators according to different studies:

  • 99.8% efficacy against influenza viruses, if fitted well, otherwise 64.5% (Noti et al. [2012]) - influenza virus is of similar size as SARS-CoV-2, around 100nm (Zhu et al.)
  • 96% protection from infection (95% certainty interval 70-99.6%; Chu et al., p. 1980)
  • 92.8% protection from clinical illness (at 57% compliance to wearing the mask; MacIntyre et al., p. 963)
  • 99.9% (▒0.1%) material filtration capacity for aerosol particles 0.3-6Ám at different flow rates (Konda et al., tables 1 and S1).

(3) Efficacy of surgical masks according to different studies:

  • No conclusive difference between the effectiveness of surgical masks and N95 masks in a large trial (relative risk ranging from +18% to -14%) (Radonovich et al. [2019])
  • 94.5% efficacy against influenza viruses, if fitted well, otherwise 68.5% (Noti et al. [2012])
  • 85.8-100% fewer coronavirus and influenza virus detection in droplets or aerosols (Leung et al., calculated from table 1b - the mean of this range [92.9%] was used for the range presented in the main text [75-94.5%])
  • 82.9% protection from clinical illness (at 66% compliance to mask wearing; MacIntyre et al., p. 963)
  • 75% fewer infections with COVID-19 even after 4 days of constant exposure (Chan et al.)
  • 81% (▒1%) to 99.6% (▒0.1%) material filtration capacity for aerosol particles 0.3-6Ám at different flow rates (Konda et al., tables 1 and S1).

(4) Chi-Chung et al., calculated from table 1, range of the 96.6% figure: 95.7-97.2%.

(5) Material filtration capacity at different flow rates for particles 300nm to 6Ám (the minimum is suitable for aerosol particles that contain SARS-CoV-2, which measures 60-140nm [Zhu et al.]):

  • 82-96% for 3-layer cotton quilt
  • 59-73% for chiffon
  • 44-54% for flannel
  • <30-51% for satin (polyester)
  • 5-55% for typical cotton (80 threads per inch, TPI)
  • 25% (▒3%) for synthetic silk

(Konda et al., tables 1 and S1, pp. 6342, 6344 - for the range presented in the main text [25-89%], the averages for each material were taken into account).

(6) Verma et al.

(7) 66% protection (95% certainty interval 48-78%, Chu et al., table 2, p. 1981). In an experiment, combining N95 masks with eye protection halved infections from the influenza virus (which is of similar size as SARS-CoV-2) (Bischoff et al. [2011]).

(8) 5.8% of COVID-19 patients in Hubai were wearing glasses daily, while in the local population, it was approximately 31.5% (Zeng et al.).

(9) At less than 1m, the risk of infection is 12.8%, decreasing at or above 1m to 2.6% (1.3-5.3%); while extending the distance from 1m to 2m approximately halves the risk (Chu et al., table 2, p. 1980).

(10) Bahl et al., Jayaweera et al.

(11) ECDC, Ong et al., Somsen et al.

(12) CDC (2009).

(13) Mittal et al.: "soap molecules ... dismantle the lipid envelope of the virus, thereby deactivating it".

(14) Disinfectants deactivate SARS-CoV-2 completely within 5 minutes (Chin et al.).

(15) CDC.

Combining these preventive measures will be more effective in reducing the virus' transmission.

Hand hygiene alone, for example, did not show a significant impact in a study, but the combination of hand-washing and face masks reduced the transmission of influenza virus (which is of similar size as SARS-CoV-2) (Wong et al.).

The measures are included in the prevention plans of many businesses and institutions as well as in governmental policies to address COVID-19.

Already in February 2020, South Korea started to distribute millions of face masks to its population (ABC News), which was associated with flattening the epidemic curve (Chi-Chung et al., p. 113).

At the beginning of the pandemic, in Western countries, there was some reluctance to be seen wearing or to recommend wearing face masks to individuals in a non-medical setting. Considerations to ensure adequate supplies for medical personnel conflicted with considerations to preventing transmissions by use of face masks by other people. "Perhaps it would also be rational to recommend that people in quarantine wear face masks if they need to leave home for any reason, to prevent potential asymptomatic or presymptomatic transmission. In addition, vulnerable populations, such as older adults and those with underlying medical conditions, should wear face masks if available." "As evidence suggests COVID-19 could be transmitted before symptom onset, community transmission might be reduced if everyone, including people who have been infected but are asymptomatic and contagious, wear face masks." (1) With widespread evidence encouraging the use of face masks, their usage was eventually recommended for the general population. An important reason for this follows from the fact that infected people become contagious before developing symptoms (2), and sometimes without developing any (3). This includes children, adolescents and adults (4). Thus, one does not know who can transmit the virus, including oneself.

(1) Feng et al.

(2) HIQA.

(3) At an average of 17-36%, Byambasuren et al., Poustchi et al.

(4) ECDC.




How Can we Prevent or Reduce Impacts to Other Global Challenges and their Targets?


Tuberculosis: The lockdown measures to reduce COVID-19 did have a positive impact in temporarily reducing tuberculosis transmission. However, that effect could easily get more than outweighed by a 3 months suspension in tuberculosis services, followed by a further 10 month periods to return services to normal, which would result in an additional 1.20 million cases of tuberculosis over the next 5 years. These negative impacts could be mitigated by rapid restoration of tuberculosis services and targeted interventions (1).

(1) Cilloni et al.                                                                                          

Malaria prevention: Whilst most malaria prevention services were able to progress during 2020, even a 25% disruption in access to effective antimalarial treatment in sub-Saharan Africa could lead to 46,000 additional deaths (1).

(1) WHO.                                                                                          

Treatment services: The COVID-19 pandemic led to the partial or complete disruption of treatment services for hypertension (in 53% of 163 WHO member states), diabetes and diabetes-related complications (49%), cancer (42%) and cardiovascular emergencies (31%) (1).

(1) WHO.                                                                                          

Food security: COVID-19 was projected to double the number of people facing food crises in low and middle-income countries to about 265 million by the end of 2020 (1).

(1) WFP.                                                                                          

Poverty: COVID-19 was projected to push 71-100 million people into extreme poverty in 2020. Long-term progress in poverty reduction is about to be reversed, conflicting with the UN SDG target to eradicate extreme poverty by 2030 (1).

(1) World Bank; UN SDGs, target 1.1.                                                                                          

Most of these impacts are caused by disruptions to economic activities, transport and social contacts. Such disruption can emerge through lockdown policies or through a disorderly process of contact avoidance and loss of trust. In low and middle-income countries, decision-makers often face a grim dilemma to choose between allowing the virus to take its death toll or to put food security and non-COVID health care at risk as a side-effect of a lockdown.


Macro Level


Which Overall Strategies Are Successful and which Problems and Solutions Do Model Projections Indicate?


An early model scenario indicated that without mitigation measures, the COVID-19 pandemic could have claimed approximately 40 million lives in 2020, but with mitigation measures, the death toll could have been reduced to around 4 million (1) (see also our article on the study). This was close to a later, more elaborate modelling of 2.09 million reported deaths and 4.19 million total deaths by end 2020, taking the countermeasures applied into account. By April 2022, the same model projects 6.59 million reported deaths or 13.9 million total deaths. Different scenarios of this study show that more severe courses of illness from the Omicron variant would lead to a higher death toll, while a third dose of the vaccine or less hesitancy against vaccination would result in a slightly smaller death toll, and 80% mask usage would reduce it even further (2) (see diagram below). This may be due to the fact that face masks can be produced and distributed faster and take effect faster than vaccines.

(1) Walker et al.

(2) IHME 2021.                                                                                              


Projected Global COVID-19 Deaths by April 2022

Diagram on projected COVID-19 deaths by April 2022.

Source: IHME 2021 (update every two weeks).


In the coming months it is absolutely critical to uphold or extend prevention measures such as mask wearing and physical distancing while also continuing and extending COVID-19 vaccination programmes, as they appear not to be sufficient to achieve and maintain herd immunity so far.





General sources of information on COVID-19:

See also our article "How Serious Is the COVID-19 Pandemic and How Long Will It Have to Be Mitigated?"


Disclaimer: The information provided in this document does not include medical advice and comes, despite being compiled with due diligence, without any liability. For medical advice, please consult a medical doctor.



Suggested citation:
Global2030: The COVID-19 Pandemic and Approaches to Combatting it. Berlin, Global Challenges Initiative e. V., 2021. (www.global2030.net/news/covid19.html).