One Year into the Pandemic: Where are we Now?
The COVID-19 pandemic has gripped the entire globe for more than a year now, resulting in more than 3 million deaths worldwide,[1] with over 570,000 deaths in the US alone.[2, 3] Infected individuals with certain comorbidities, such as obesity, remain at a significantly greater risk for hospitalizations and death. And after a year, many businesses remain closed or only partially opened, which continues to create economic hardship for many while taking a toll on the economy. Vaccines offer hope, but the initial roll-out of the vaccines in the US was at first slow, and the public health community has issued mixed messages on the extent to which vaccines offer a pathway to normalcy.[4-8]
In this blog entry, we briefly review where we are at now, one year after all of this started. For basic data on overall trends in infection rates globally and in the US, the best sources remain the World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC); we will not repeat that information here. Instead, with a focus on the US, we provide brief updates on the following five key topics: (1) epidemiology (transmission rates, risk factors, and hospitalization rates); (2) mortality (death rates and “excess deaths”); (3) economic impact; (4) virus variants; and (5) vaccines.
Epidemiology
Let us start with transmission rates. In the early days of the COVID-19, concerns were that transmission rates for the emerging virus were considerably higher than viruses of the past, perhaps in part to its primarily airborne transmission.[9, 10] Did that turn out to be the case? The intensity of an infectious disease can be quantified through a reproduction number, referred to as “R(0).” These values are an estimation of the number of people an infected patient will spread it to while they are infected.[11] During the H1N1 outbreak in 2009, the estimated reproduction number clustered around 1.5. In contrast, preliminary estimates of the SARS-Cov-2 reproduction number have been considerably higher, ranging from 2.8-5.5 in the absence of quarantine and social distancing measures.[11-13] So the virus does seem to transmit “more easily” than some other past known viruses. Another important disease characteristic is that transmission can be sourced by either infected symptomatic or asymptomatic individuals, though studies agree that transmission rates are higher among symptomatic individuals.[14, 15]
Now we turn to those who are most likely to get the disease—not just who becomes symptomatic, but who is at risk for the virus’s more serious symptoms. First, age appears to be one of the most important risk factors, with older individuals at considerably higher risk for hospitalization and death.[16] Though the vast majority of COVID cases in children are mild,[17] children with some chronic and rare diseases can also be at considerably higher risk. Among adults, throughout the pandemic studies have consistently shown elevated COVID risk among those with obesity (i.e., body mass index [BMI] more than 30 kg/m2), diabetes, heart disease, chronic kidney disease, chronic obstructive pulmonary disease (COPD), cancer, and some rare diseases that impact the immune system.[16] In addition, smokers are at considerably higher risk for COVID. Several studies have sought to determine the effect of underlying conditions on infection severity. Regarding obesity, it is believed that predispositions include inflammation, altered physiology, and immune disfunction. Similarly, diabetes imparts a chronic low grade inflammatory state in patients that increases susceptibility to infections, especially when combined with impaired T-cell function and increased interleukin 6. It is also believed that the interaction of COVID with the renin-angiotensin aldosterone system may contribute to the overrepresentation of hypertension within patients showing severe symptoms.[18]
The importance of these risk factors can be seen in the hospitalization data. In recent months, COVID-related hospitalization rates have decreased; for example, between January 5, 2021 and February 16, 2021 new hospitalizations saw a 62% decrease from 18,006 down to 6,841, with an average daily admission decrease of 21.8%.[19] In terms of risk factors, hospitalization rate in COVID-19 patients with cardiovascular disease was 27.8%, 34.6% in patients with chronic lung disease, 36.1% for patients with chronic metabolic disease, 48.3% in patients with obesity, 14% in patients with neurological diseases and 49.7% for patients with hypertension.[20] A recent study found that a community-dwelling 5,416 adults with COVID-19–associated hospitalization, 55% of them had obesity, 49% had hypertension, 33% had diabetes, 16% had severe obesity, 13% had asthma, 12% had chronic kidney disease, 9% had a history of coronary artery disease, 6% had COPD, and 4% had a history of stroke.[18]
Mortality
Mortality rates due to COVID-19 have followed trends in U.S. infection rates; as of October 2020, COVID-19 had become the third leading cause of death in the 45-84 age group and second in those older than age 85.[21] The mortality rate of COVID-19 for all per 100,000 people in the general population is 171, placing it significantly higher than that of motor vehicle traffic deaths, which is 11.5 per 100,000 people.[22, 23] As of January 2021, as COVID-19 infections continued to rise it quickly became the leading cause of death in the U.S., at a rate of 3,000 deaths per day.[24]
Perhaps the best way to assess the mortality burden of COVID is to look at the number of “excess deaths” since the pandemic began; that is, the number of deaths recorded that exceed the number that we would statistically “expect” over the same time period (given population characteristics). Data from CDC supports such calculations, and reporters from The New York Times recently calculated the number of excess deaths for the US and by state.[25] From March 15, 2020, to February 20, there were 574,000 excess deaths recorded, representing a 21% increase over what would normally be expected. Given how closely this number tracks with the total number of COVID deaths, this suggests that the majority of the COVID deaths are deaths that would otherwise have not occurred.
It is interesting to also examine how the rate of excess deaths varies across the U.S. The U.S. has to some extent been a natural experiment in health policy directed at the pandemic, with states more or less free to determine the COVID response.[26] In New Jersey, where the pandemic lockdown was among the strictest and most far reaching of any state lockdown, the rate of excess deaths was 32% at the close of the March 2020 to February 2021 time period—11 percentage points higher than the national average.[25] Florida, in contrast, has become known as the state with the shortest period of full lockdown followed by relatively mild restrictions and weak enforcement of those restrictions; it is in the top 10 “least restrictive” states.[27]
Surprisingly, Florida’s rate of excess deaths is 17%– 4 percentage points below the national rate and 15 percentage points below the more restrictive NJ.[25] One concern with this comparison is that NJ, due to weather, has residents spending comparatively more time indoors, whereas Florida’s warmer mild weather supports more time spent outdoors, where transmission rates are lower. However, even California, with its mild weather and “top 10” status in terms of COVID-related restrictions,[27] had 27% excess deaths—more than 10 percentage points higher than Florida. It is of course too soon to conclude from this that stringency of restrictions failed to have much impact, but these data suggest that might be the case.
Economic Impact
While the humanistic impact of COVID-19 has appropriately been the primary focus, the pandemic has also taken a substantial economic toll in the U.S. and abroad.[28-31] The real gross domestic product (GDP) fell a total of 3.5% by the end of 2020. The total economic cost of the COVID-19 pandemic in the U.S. has been estimated at more than $16 trillion, approximately 90% of the annual gross domestic product of the U.S. This translates to an estimated loss of nearly $200,000 for a family of four. Approximately half of this amount is from lost income associated with the pandemic’s recession, while the remaining economic loss is the result of shorter lives and sickness.[32] Among the hardest hit sectors in the US economy have been the services and entertainment industries, which have relatively high labor costs.[33] U.S. small businesses reported an average 30% loss in sales midway through 2020, with 60% reporting a net negative loss and nearly 25% reporting losses in excess of 50%.[34] There are some signs of hope. The GDP increased at an annual rate of 4.1% in the fourth quarter of 2020, reflecting both the continued economic recovery from the pandemic-related effects.[35]
The provider side of the U.S. healthcare industry has also experienced significant losses, with costs estimated between $9.6 billion and $16.9 billion in 2020. Of these costs commercial payers are expected to cover between $5.6 billion and $9.9 billion, and Medicare is expected to pay the remaining $3.5 billion to $6.2 billion, which will include the treatment of uninsured patients. The burden on state Medicaid payments has been substantial. Costs for hospitalizations for COVID-19 are expected to total $546.6 billion for payers.[36] While the health industry as a whole was probably less impacted than many other industries, the pandemic has resulted in substantial cancellations and delays in treatment for chronic disease and elective procedures, both of which can be large revenue generators for hospitals and health systems.[37]
Variants
There has been a lot of concern lately over the role of COVID-19 variants, and whether the existence of variants could prolong the pandemic. The SARS-CoV-2 Interagency Group (SIG) partnered with the CDC to establish a classification scheme for variants of SARS-CoV-2. There are three classes of SARS-CoV-2 variants: variants of interest, variants of concern, and variants of high consequence.[38]
Variants of interest, also known as B.1.526, B.1.525, and P.2., have specific genetic markers that have been associated with changes to receptor binding, reduced neutralization by antibodies generated against previous infection or vaccination, reduced efficacy of treatments, potential diagnostic impact, or predicted increase in transmissibility or disease severity.[38] Variants of concern, also known as B.1.1.7, P.1, B.1.351, B.1.427, and B.1429, have an increase in transmissibility, more severe disease (increased hospitalizations or deaths), significant reduction in neutralization by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures.[38] Currently, the top three variants in the U.S. are B.1.1.7, B.1.351, and P.1 with 4,690, 143, and 25 reported cases, respectively (updated March 11, 2021). Florida is currently the state with the highest reported B.1.1.7 variant at 738 cases.[39] Variants of high consequence, which there are currently no SARS-CoV-2 variants, have clear evidence that prevention measures or medical countermeasures (MCMs) have significantly reduced effectiveness relative to previously circulating variants.[38]
Vaccines
To date, there are 13 COVID-19 vaccines that have received authorization for use in at least one country.[40] More than 1.03 billion vaccine doses have been administered worldwide. This is equal to 13 doses for every 100 people (updated April 26, 2021).[41] The U.S. is the country with the most administered vaccines, followed by China, United Kingdom, Brazil, Israel, and Russia.[42]
Currently, there are three vaccines that are authorized and recommended to prevent COVID-19 in the U.S.: Pfizer-BioNTech, Moderna, and Johnson & Johnson/Janssen.[43] The Pfizer-BioNTech vaccine, the first to be authorized in the U.S., is a messenger RNA (mRNA) vaccine that gives instructions to the immune cells to make a harmless unique piece of what is called the “spike protein;” the cell then displays the spike protein on the surface of the virus.[44] After the cells make copies of the protein, they destroy the genetic material from the vaccine. The body recognizes that the protein should not be there and builds T-lymphocytes and B-lymphocytes that will remember how to fight the virus that causes COVID-19 if ever infected in the future.[45] Moderna, the second authorized vaccine in the states, is also a mRNA vaccine. Both Pfizer-BioNTech and Moderna are administered in two doses. The Johnson & Johnson/Janssen is a single-dose viral vector vaccine, which uses a modified version of a different virus (the vector) to deliver instructions to cells. Inside the shell of the modified virus, there is material from the virus that causes COVID-19, which is called a “viral vector.” Similar to mRNA, the vector vaccine gives cells instructions to make a protein that is unique to the virus that causes COVID-19 and makes copies of the protein, prompting the body to build T-lymphocytes and B-lymphocytes.[45]
Like any virus, SARS-CoV-2 naturally undergoes mutations over time. The COVID-19 vaccines that are currently in the development stage and or have been approved are expected to provide at least some protection against new virus variants. Any changes or mutations in the virus should not make vaccines completely ineffective.[46] Moderna has started work on updating its mRNA vaccine to match spike mutations in 501Y.V2, also known as the virus of concern B.1.531. The biotech company, based in Cambridge, Massachusetts, says it also intends to test the effectiveness of a third dose of its original coronavirus vaccine, and is looking into the possibility of a multivalent vaccine.[47]
As of April 25, 2021, there have been 228,661,408 doses have been administered in the U.S. This breaks down to 139,978,480 people who have received at least one dose and 94,772,329 people who are fully vaccinated. More than 47 million people have been fully vaccinated by the Pfizer-BioNTech vaccine, while about 39.5 million received the Moderna vaccine and roughly 8 million got the Johnson & Johnson/Janssen vaccine.[48]
The Biden administration has promised Americans that every adult in the country will be eligible for coronavirus vaccine by the end of May 1, 2021.[49] The rate of vaccinations has increased to an average of 2.75 million shots a day as of April 25th.[50] Experts have estimated that in order to reach herd immunity, 70-90% of the population needs to acquire resistance to the coronavirus.[50]
(John Schneider, PhD, Karen Beltran, BS, and Cara M. Scheibling, MBA) (April 27, 2021)
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