The Deceleration Trajectory of COVID-19: Part Two

by: Laurence Svirchev, CIH and Vivian Danping Sheng


(Overview updated 2021-03-21). Recent data from the World Health Organization (WHO) demonstrate a sustained six-week long deceleration trend for new COVID-19 cases and deaths up to 2021-02-16. However, a four week-long counter-trend then developed with an increasing number of cases. Vaccination rollouts are still too new to account for either the deceleration or acceleration effects. Predictably, some sectors of society including politicians and public health officials are once again calling for reducing or ending strict public health measures. The year-plus experience with SARS-CoV-2 indicates that ending such measures consistently results in new outbreaks and prolongation of the disease, mortality, misery and suffering. Instead, public health measures still need enforcement and enhancement to ensure an ever-increasing decline of new cases and deaths in conjunction with increasing the rate of vaccination. As Dr. Tedros of WHO stated on 2021-03-19, “These are worrying trends as we continue to see the impact of variants, opening up of societies, and inequitable vaccine rollout.” In spite of the changing numbers, the basic analyses presented in this publication still hold, including the US and Europe being the drivers in the pandemic.

The Data

WHO Data for COVID-19 Weekly Epidemiological Update as of 28 February 2021

Figure 1 shows the COVID-19 acceleration and deceleration curves starting from the first diagnoses of a “pneumonia of unknown etiology” in China on December 28, 2019. WHO presents graphed macro-data from their six administrative regions. The administrative regions are useful for an overview of the trajectory of the pandemic but are difficult to analyze due to the huge geographic, climatic, cultural and political variations in each region. For example the Americas represents the southern and northern hemispheres, each with inter- and intra-continental and -country rates. Parsing can be done by referring to the regional analyses and country-by-country data contained within the Weekly Epidemiological Update. Nevertheless, Figure 1 clearly shows the long trajectory and sharply increasing pandemic cases for about 52 weeks, then the subsequent sharper deceleration of new cases until the uptick of the last reporting period.

Parsing the International Data

Table 1 extracts data for selected countries and regions. It shows that the United States has the greatest number of cumulative cases in the world (28 million), accounting for 21% of global cumulative cases. By comparing, for selected countries, the cumulative cases/100K population with the global case rate, we derived a relative rate, a comparison to the global cumulative case rate of 1,456/100k population.

The United States of America has the highest relative case rate, 8,512, or 5.8 times the global average. Only a few European countries exceed the United Stares (Czechia, Montenegro, San Marino, Gibraltar, and Andorra). The UK, Brazil, Europe, South Africa, the Russian Federation, and Canada all exceed the global average. At the other extreme of the population case rate,  Korea, New Zealand, China, and Viet Nam have negligible population case rates.


Figure 2 from the Government of Canada COVID-19 Epidemiology Update of 2021-02-27 shows a clear acceleration of new cases starting about August 30, a leveling off in the middle of December and a rapid and seven- week sustained deceleration starting on 27 December 2020 until the third week of February 2021. (The added red lines have been added for interpretation purposes. The gray bar indicates incomplete reporting. The site is updated on a daily basis and will differ from the 27 December data).

Canada: Coast to Coast by Provinces and Territories

Figure 3 graphs Case Rates Across Canada (source: BCCDC) compares the case rates across Canada from August 2020 to February 2021. Case rates for the major Provinces are all declining up to the 2021-02-03 cut point. The trend lines illustrate the uneven case rates (cases/100K population) in the different provinces, some of which exhibit a ‘roller-coaster’ effect. BC’s flux is less radical than many provinces, yet it demonstrates no power to reach the baseline relative to other provinces it had between August to mid-October 2020. Smaller population Provinces and Territories have very low rates. Although the deceleration of case rates for major provinces commence on different dates, their minima coincide at the same 2021-02-03 end-date for this data set as shown by the inserted blue vertical line.



Canada: British Columbia

Figure 4 (source:BCCDC) shows the number of cases of COVID-19 from Week 3 of BCs epidemic to January 2021 (55 weeks). The CDC COVID Response Plan phases is on the top line. While the purpose of the BCCDC graph is to show likely sources of infection, the general acceleration-deceleration trend line is more important for the purposes of this analysis.

For the first 27 weeks of the pandemic, BC performed well at controlling the local epidemic. On week 31 (29 July inserted vertical blue line) the number of cases began to increase, expressed as a gentle slope. Week 42 (14 October) signaled a rapid acceleration of the curve until week 47 (18 November). Thereafter the number of new cases declined substantially until the last reported day 2021-01-23.


Figure 5 (source:BCCDC) states the “Start Of School Does Not Result in Significant Increases in Community Transmission.” The school year in BC started on 14 September. The graph indeed does shows a weak increase in transmission among people aged 5-18 (students). The data also shows that community transmission start to increase by the end of July. Within two weeks after the 14 September return to school, community transmission in fact sharply accelerated to a peak of about 800 cases/day on about 24 November. After this date, the number of daily cases began to sharply decline.




A general comparison between data expressed in WHO international (Figure 1) and Canada data (Figures 2-5) confirms a profound and prolonged deceleration of the pandemic curve with the exception of last weekly reporting period. Chronologically and geographically, the international deceleration is occurring roughly in the same time period as the beginning of the pandemic and it is concurrent in both the north and south hemispheres. These two observations suggest that seasonal variations are not responsible for the pandemic accelerations and decelerations.

Even countries with the highest cases rates are declining in concord with the general deceleration, for example the United States (new cases down 29%). International vaccination programs have started only recently in January 2021, so this public health measure cannot yet account as a critical factor for the international deceleration. The recent 7% uptick may be a result of new and more potent variants of SARS-COVID-19-2. (The authors have no expertise in µbiology and cannot comment on the role of the natural cycle of the virus nor variants until their role in case rates is scientifically clarified and trends verified by real-life experience).

Canada Trends

The Canadian deceleration is in general accord with the international trend lines, the rates for the major provinces all reaching similar minima in the beginning of February (Figure 3). Because of Constitutional and historic issues, public health in Canada is mandated to the provinces. Consequently, public health and social measures have been inconsistent, with marked differentiation in timing and rigor of application, and subject to political control rather than coordinated best practices.

What has truly and critically helped Canada though the whole pandemic period is the social distancing of the Canadian population from the exponentially higher risk US population through the closing of land borders.

While BC has had consistently lower new case rates than Ontario, Québec, Saskatchewan, and Manitoba, the BC trend has stubbornly not declined to baseline. The BC trend is particularly instructive since public health orders on masking, public gatherings, and shopping activities have been progressively stricter but also consistent. They have not been not clawed back unilaterally as has happened in some provinces, only to have them restored when new outbreaks occur. Even after the late November 2020 decline in new cases, public health measures in BC have become stricter, such as the 2021-01-08 Minister of Public Safety order requiring face coverings in all public spaces.

There is, however, a particular curiosity about BC’s public health measures. Figure 5 declares that the “start of school does not result in significant increases in community transmission.” The BC data shows the contrary: an acceleration in the total number of cases a few weeks before the startup of school and within two weeks post-startup, a sharp acceleration of the epidemiological curve.

Such an acceleration is entirely predictable and inevitable unless other prevention measures had been put into place. Return to school involves more than young people age 5-18. Schools are run by workers including teachers, administrators, food service, janitorial, truck and school bus drivers, and a host of other occupational activities that involve interaction with the rest of the workforce. Return to school also means that typical family practices of keeping children home (socially isolated) comes to an end. Adults have more time to freely associate in public, and even loosen self-imposed restrictions in the interest of celebrating the semblance of freedom.

The appropriate, data-based conclusion for the BCCDC should have been something like, “Community transmission started to accelerate in tandem with the return to school on 14 September 2020. Extra measures should have been taken to ensure that the return to school did not provoke an increase in community transmission.”


Recent data shows a six-week steep deceleration of new cases in the SARS-CoV-2 pandemic, then a 7% uptick for the week ending 2021-03-28. This is the first coherent signal that the pandemic has substantially decelerated internationally. The proviso is that countries such as Viet Nam, China, New Zealand, Korea never joined the pandemic curve after they controlled their initial outbreaks. A second proviso is that the African continent with the exception of the Republic of South Africa has had extremely low rates.

Our first conclusion is that the drivers of the pandemic are the most developed large economies, the United States and Europe, not the developing world. This data-based conclusion is counter-intuitive. The United States of America with the highest health expenditure per capita in the world (USD10,600) and simultaneously the highest case rate of COVID-19 in the world, almost six times the international average. The UK’s rate is 4.4 and Europe as a whole is 2.8. The health-care system in the United States is highly privatized; in contrast the Europe’s systems are highly socialized. In either case the sheer financial and medical power of those systems was inadequate to defend themselves against a virus that China had defeated just as the virus reached Europe and quickly thereafter the United States. The inability of major economies to systematically lower rates of COVID-19 to background  appears to be tied into a tricky proposition: the wealth of nations and their social systems.

It is widely known that pandemic resistance in the United States was designed and destined to fail due to the bizarre, charlatan, medically-illiterate Trump presidential administration and their equally weird conspiracy-minded cronies throughout the country. In addition to failing to support healthcare systems throughout the country and invoke emergency powers to produce N95 respirators and medical instruments, they also quit the bastion of world pandemic leadership, the World Health Organization. Fortunately the new US administration has rejoined WHO and it is taking a number of strategic initiatives  to combat the pandemic.

Oddly, however, new cases in the United States and began to fall at about the same time as the rest of the world (excluding the Pacific Region and Africa). The US CDC reported on 2021-03-05 that “There has been an overall decline of 74.9% of the 7-day moving average since the highest 7-day average of 249,360 on January 11, 2021.” In other words, the US deceleration began during the last days of the Trump regime bankrupt COCID-19 policies.

Our second conclusion is that the new trend lines challenge previously held thinking that, “While COVID-19 accelerates very fast, it decelerates much more slowly” (Tedros, WHO, 2020-04-13).  But what are the causes of the new trend? What are the relations between the natural causes, and what are the effects of anthropogenic (social, medical-prophylactic, political) interventions? On February 7, 2020 at the beginning of the [not yet declared] pandemic, the US CDC characterized COVID-19 as an “emerging, rapidly evolving novel coronavirus“. This statement is as true as ever, and as the last year has shown, there will be many surprises ahead.

In the beginning, China got hit by an unprecedented surprise attack. Other countries such as Viet Nam, Korea, New Zealand, and a few others had “early warning” and rapidly responded with time-tested public health measures. They responded  rapidly and have had great success in suppressing SARS-CoV-19 through rigorous application of traditional public health measures including quarantine, border closings, travel bans, social distancing, barrier mask wearing, prohibitions on public events and celebratory rituals and restaurant closings. they tested huge numbers of people.

Their public health and political and leadership did not vacillate during the pandemic. Each of these countries have very different political, social, and cultural dynamics, yet they all have the characteristics of strong public health measures from political leadership and, we emphasize, social discipline in accepting and implementing these measures. In other words, these countries self-inoculated their populations through social measures, effective enough to drive the infection rates to negligible.

Our third conclusion is that these countries drove infection rates to background noise without vaccines. Vaccines will become part of a robust public healthcare system to prevent re-infection.

Our fourth conclusion has to do with occupational health, overlooked or downplayed by many public health authorities around the world. Epidemic control is typically the domain of Public Health governmental organizations, and the control of workplace hazards is typically vested in a Ministry of Labor. The SARS-CoV-2 pandemic represents a cross-over between public and occupational health; the etiological agent is not a chemical agent only found in specialized manufactories or a mineral agent like silica found in construction. The agent is an infectious organism that travels anywhere humans go, constantly  seeking new hosts.

This is not just a matter of protecting workers during clinical procedures from infected patients. Within healthcare there are multiple other workers: in patient recuperation, long-term care, and laboratory settings in which workers require N95s to prevent aerosol transmission. One of the authors has direct experience with this in BC. While having blood drawn in a laboratory that sees hundreds of patients of unknown COVID-10 per day, he was told that technicians were not allowed to wear N95s for two reasons: they had to be reserved for clinical aerosol-generating procedures and there was no need for specialized procedures other than “standard precautions.” They were even forbidden to use N95 and could only use inefficient surgical masks.

Both reasons are nonsense: one year into the pandemic, N95 are plentiful. Research has confirmed over and over that aerosol transmission of  SARS-CoV-2 is not a theoretical proposition, it is real. This means that to further control transmission, Personal Protective Equipment such as N95 and increased ventilation to ensure clean respirable air are required in manufacturing, food preparation, retail-wholesale, emergency response, and transportation workers.

Right from the beginning of the pandemic in March 2020, various occupational safety and hygiene associations in Korea, Hong Kong, the United States, and elsewhere began developing safe work procedures in multiple industries to protect workers against transmission of SARS-CoV-2. The American Industrial Hygiene Association (AIHA) established a free COVID-19 resource center for employers and workers and later in the fall of 2020, a set of Safe Return to Work  advisories. Recently, the AIHA joined together multiple other professional associations to produce a Joint Consensus Statement on Addressing the Aerosol Transmission of SARS CoV-2 as a vital measure to protect both the workforce and the general population. Workplace Health Without Borders, a volunteer organization, has been tireless in promoting occupational health during the pandemic, sponsoring frequent webinars with prominent international experts.In Canada, an ad-hoc group of physicians, occupational health and safety experts, engineers, and nursing professionals called on the federal and provincial governments to protect workers from aerosol transmission. The letters were signed by 658 professionals and endorsed by  19 professional organizations and worker unions.


Recent data from the World Health Organization (WHO), the Government of Canada, and the United states CDC have  demonstrated a sustained deceleration trend for new COVID-19 cases. The news of this decrease is accompanied by the now familiar and inevitable out-of-tune chorus of ‘open the economy’ being sung again particularly in the United States.

Given that there is no solid scientific knowledge that the trend line is irreversible, then it must be forcefully and plainly stated that:

  • The decelerating trend lines cannot be interpreted to justify lifting social and economic restrictions aimed at placing multiple barriers to dampen and prevent the spread of the virus (breaking the chains of transmission).
  • SARS-CoV-2 has a proven ability to exploit all open portals and vectors leading to consequences of additional burdens of misery, disease, death, and failed economic opportunities.
  • The role of new variants is niot well-understood. They post a powerful potential to reverse the deceleration curve.
  • The role of aerosol transmission of the disease in occupational and public settings is a sadly neglected link in the chains of transmission.
  • Adequate supplies of N95 and elastomeric respirators are available and there is no longer any excuse for solely reserving them solely for clinical aerosol-generating procedures.
  • Vaccines are critical, but the progress of vaccinating the most vulnerable populations is a lengthy process on account of multiple factors, including the international manufacturing supply chain, failure to set up distribution  infrastructure well in advance to vaccines becoming available, different vaccination policies across world, the time it takes for vaccination to take hold in individuals.

The year-plus experience with SARS-CoV-2 indicates that ending such ‘open the economy measures consistently result in new outbreaks and prolongation of disease and death, misery and suffering. Figure 5 with regard to opening schools in British Columbia Canada is an example of this dynamic. Instead, public and occupational health measures still need enforcement and enhancement to ensure an ever-increasing decline of new cases and deaths in conjunction with the increasing rate of vaccination.



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