Truth #1: A vaccine is essential for true herd immunity.
As the COVID-19 pandemic was first gathering force, we began to hear about the idea of herd immunity as one possible response to the crisis. Herd immunity means that when enough people in a given group have developed immunity to a disease – whether by contracting the disease and recovering, or by vaccination – it has a hard time spreading any further.1
Theoretically, herd immunity can be reached by doing nothing, and simply letting the disease run its natural course until the minimum percentage of the population has been exposed (estimated between 55% to over 80% of the population for COVID-19).2 This is sometimes also called natural immunity.3
For example, Sweden’s approach to COVID-19 has become associated with the herd immunity strategy when that country declined to order a strict lockdown on schools, restaurants, and bars, unlike most European countries. As things turned out, they experienced much higher rates of infection and death than their neighbors.4
In contrast, vaccination stimulates a person’s immune system to produce immunity to a specific disease, protecting the person from that disease. (In some cases a vaccine may not completely prevent infection, but you may have a milder form of the disease.)5
When epidemiologists talk about herd immunity, they mean a high percentage of a community being immune to a disease through the combination of vaccination and/or prior illness – not just natural immunity.6
In this illustration we can see infection continuing to spread (orange) until blocked by immune persons (gray):
Diagram adapted from Bloomberg/Quint. How Herd Immunity Works, a Possible Key to the Covid Pandemic’s End. *JAMA. Planning for a COVID-19 Vaccination Program.
There are a lot of problems with the natural immunity-only perspective. In addition to the widespread economic disruption we have seen, allowing an unchecked spread of disease threatens the health of people who are at high risk of developing severe effects from COVID-19. Recently we have seen that these groups have grown to include even younger people.7
Considering the costs
Attempting to achieve natural immunity for COVID-19 could place millions of people at risk and, to make matters worse, it may not even be all that effective.
First, the risks from contracting COVID-19 are high. For example, while some have compared it to chickenpox, it is 100 times more lethal than chickenpox.3 While chickenpox has never killed more than 150 Americans in a year, COVID-19 is killing almost 1,000 Americans every day.3, 8
In order to achieve 80% natural immunity, over 260 million Americans would eventually have to become infected. Assuming an estimated fatality rate of 0.5%, more than 1.3 million people would die before we reached natural herd immunity.9
Second, in general, natural herd immunity will always leave pockets of those who have not encountered a pandemic disease.6 In addition, it’s not yet clear how long people who recover from COVID-19 will remain immune to reinfection.10 Both of these groups of people may remain targets for the disease, as well as candidates for renewed disease transmission.6
For example, before we had wide access to a measles vaccine, a majority of the population was already immune through natural immunity. Despite this, millions of people would contract measles each year; many would sicken, some would die.11
The same would be true with COVID-19. Without a vaccine, we could expect a vast amount of ongoing death and suffering from COVID-19, even with natural herd immunity.11
Relying on natural herd immunity as the sole strategy to address the COVID-19 pandemic could lead to unnecessary illness and death. We do need herd immunity, but we need it in the sense epidemiologists use the term, as a combination of vaccination and natural exposure.
Truth #2: Widespread availability of a vaccine will take time.
Confidence is growing that we will have at least one, and perhaps several, COVID-19 vaccines approved before the end of 2020.1 Yet while three manufacturers have said that they intend to have a vaccine ready this fall, it’s not clear that they will be able to support a mass vaccination campaign at that time.2
The real question is when most people – not just a few – will have access to an approved COVID-19 vaccine.
Drug makers are working rapidly to expand their manufacturing capacities, but they face a daunting task. Experts are saying that manufacturing and distributing the billions of doses that will be needed will be a huge logistical challenge, and may simply not be achievable in the short term.3
In this article we will look at some reasons why it may be some time in 2021 before most of us can expect to roll up our sleeve. Prior to then, we should expect the government to prioritize the availability of a vaccine to healthcare workers and those who are at high risk of developing severe COVID-19 disease, such as the elderly and those with underlying health conditions.2
Before a new vaccine can be manufactured, it has to be designed and tested first. This is the part of the process that has drawn the most attention so far, as multiple vaccine candidates have leapt from the lab to human trials at record speed.4
A big reason for this fast pace is that researchers are drawing on decades of related vaccine work, for example in Ebola and the human immunodeficiency virus (HIV). This research has yielded enormous insight into the immune system and novel vaccine platforms, like DNA and RNA. We are seeing researchers, labs vaccine platforms and testing infrastructure rapidly pivoting against COVID-19.5
Vaccine makers are already very busy making the vaccines we already know and use – over five billion doses every year. We will need to maintain production of these existing inoculations — including the seasonal flu — that use some of the same materials and manufacturing capacity. At the same time, we need to gear-up to produce additional billions of doses of a new COVID-19 vaccine.4
Pharmaceutical makers began spending millions of dollars to build-out new manufacturing capacity – long before critical phase 3 clinical trials have started. This is not only to be ready in case their vaccine candidate turns out to be effective, but also to quickly make available the tens of thousands of doses that will be needed for large-scale phase 3 clinical trials.6
Manufacturing capacity has also benefited from a very forward-looking stance adopted by the vaccine industry, with an able assist from the U.S. Biomedical Advanced Research and Development Authority (BARDA). They have been helping biotech companies to invest heavily in developing “surge” manufacturing capabilities and vaccine platforms since the early 2000’s.7
While the government has contributed large sums to this effort, manufacturers are well aware that they are working “at-risk,” meaning they may not recoup their investment if their vaccine is not approved.6
But the manufacturing supply chain also includes very mundane items like glass vials, rubber stoppers and sterile needles – now suddenly needed in huge amounts. Experts are warning about potential shortages of these items, and it is not clear that the shortages can be quickly corrected. For example, even before COVID-19, we were faced with a critical shortage of the particular kind of sand needed to create high-strength medical glass vials that could impact widespread supply of a COVID-19 vaccine.4
Considering these barriers, it’s not surprising that most manufacturers are predicting they will be able to produce only relatively modest amounts of vaccine this year, perhaps in the tens of millions of doses (although some predict more).2
A Duke University health care economist recently told a panel that there is “no way” a new vaccine can be produced at scale this year. He said that while we might be able to treat some high-priority people, “…the average person won’t be vaccinated this year.”8
Distribution includes getting the vaccine where it needs to go, prioritizing who goes first, and actually making the injections. Each of these steps presents its special challenges.
We will need over five billion doses to vaccinate at least 70% of the world population, or perhaps 10 billion if people need more than one dose.9 Just physically moving that amount of vaccine is a big job.
For scale, consider that one Boeing 777 freighter can fit exactly one million refrigerated vaccine doses per flight. That means we’d need 1,000 flights to deliver one billion doses of a new COVID-19 vaccine.10
Here in the U.S. we have a robust process to deliver large amounts of vaccine to hospitals, clinics and providers over a short period of time. But it’s not perfect.11
For example, historically around one third of vaccines are accidentally frozen in the shipping and storage stages, making it useless.12 That means even more vaccine needs to be made and shipped.
To prioritize administration of a limited supply of COVID-19 vaccine (if there is one), the Centers for Disease Control (CDC) is planning a five- tiered approach drawn from the 2009 H1N1 influenza pandemic. For example, Tier 1 (the highest) includes critical healthcare workers, public services like police and fire, and clinically high-risk populations. The CDC approach will also weigh the performance of each approved COVID-19 vaccine against the needs of each tier.13
But any large-scale administration program will be complicated by the need to minimize the spread of COVID-19. We may need to take unusual steps such as community vaccination sites, curbside or parking lot immunizations, and one-way traffic in clinics.14
At least one COVID-19 vaccine could be available as quickly as this fall. However, practical considerations such as hard limits on manufacturing capacity and critical supplies could delay the availability of vaccination to many Americans until sometime in 2021, or even later.
Truth #3: An approved vaccine is no guarantee that life will soon return to normal.
There are growing indications that we may have at least one, and perhaps several, COVID-19 vaccines available before the end of 2020.1
Some people are misinterpreting exactly what this means. First, as we have seen, it is unlikely that any new vaccine will be broadly available until well into 2021. But second, The New York Times reports that “many” Americans expect that a vaccine against COVID-19 will soon allow us to resume our pre-pandemic lives. One person said, “I’ll start taking the subway and going to the office in the fall when we have the vaccine.”2
In fact, it is not certain that we will simply carry on with life as we did before.
Vaccines are variable
Vaccines vary widely in how effective they are, and how long they last. For example, one smallpox vaccination lasts a lifetime, and is extremely effective at preventing the disease. That’s one reason why smallpox has been eradicated worldwide.3
At the opposite end of the spectrum we have the seasonal flu vaccines, which don’t always work, and which in any case need to be modified to address the predominant flu virus each flu season.3
We simply don’t know where the first new COVID-19 vaccines will fit along this continuum. Some are speculating that the first examples may only be partially effective, only mitigating the severity of the disease, instead of completely preventing it. And epidemiologists are cautioning that even new and improved versions are unlikely to deliver perfect immunity.4
Then there is the question of how long their protection will last. Again, there is no way to know this until many people have taken the vaccines and we see what happens over time.3
All that said, if we had a vaccine that could “only” reduce the severity of COVID-19 by reducing symptoms and hospitalizations, that would be a big win.2
However, failing to properly set expectations might hinder vaccination compliance, which we’ll turn to next.4
Concerns about vaccine safety are widespread and pre-date the pandemic. Despite decades of proof that vaccines are safe and effective, vaccination rates rarely achieve the clinical targets set for them, and are actually declining in many countries.5
Last year only 72% of those surveyed in Canada and the U.S. agreed that vaccines are safe, while in Western Europe only 59% said vaccines are safe. In 2019, the World Health Organization (WHO) listed “vaccine hesitancy” as one of 10 major global health threats.5
Image data source: World Health Organization: Ten threats to global health in 2019.
Vaccine hesitancy & COVID-19
In order to control the disease we will need a vaccination rate as close as possible to the herd immunity threshold. That is the only way to limit the total number of infected people in the population and protect vulnerable populations.6
Yet beyond the generalized vaccination reluctance described by WHO, there is concern that that many Americans are considering not getting vaccinated against COVID-19. In a recent poll, only 49% of people in the U.S. said they intend to get a COVID-19 vaccine (20% say they would not, while 31% said they were not sure).7
The reason this is worrisome is because, based on a variety of factors (biological, environmental, behavioral), the herd immunity threshold for COVID-19 may be between 55% and 82% of the population.6 An epidemiologist would say that means we need up to 82% of the population to be immune from COVID-19 through either having been sick and recovered, or being vaccinated.8
By comparison, here in the U.S, we typically see overall the influenza vaccination rate hovering in the low-to-mid-40% range.9 That’s not as bad as it looks, since the flu isn’t as transmissible as some other diseases, so the herd immunity threshold for flu is around 50%.10 However, COVID-19 has a higher transmission rate than the flu, which is why its herd immunity threshold is so much higher (~80%).11
Health experts argue that we can’t settle for a flu-like mid-40% vaccination rate. One reason is that not everyone will benefit from a vaccine, or be prioritized to receive it.12
As with any vaccine, we know that some people will be ineligible for COVID-19 vaccination due to age, compromised immunity, or preexisting medical conditions.6
If the polling is accurate and only 50% of Americans get vaccinated, further reductions in the number of vaccinated persons due to ineligibility or inefficacy could lead to herd immunity population below the threshold for COVID-19.6
Just as we don’t yet know how long a vaccine may protect us, we also don’t know whether surviving COVID-19 creates immunity to future infection, or if so, for how long.3
We can imagine a scenario where we do have a vaccine, but it is only partially effective, and not enough people are vaccinated to achieve herd immunity, whether through hesitancy or lack of access.
In this case a vaccine would only be one tactic to control COVID-19 – we would still need to continue social distancing and mask-wearing to slow and control the pandemic.3
References – Myth #1: Herd immunity
1. ScienceAlert. Here's Why Herd Immunity Won't Save Us From The COVID-19 Pandemic. Posted March 30, 2020. Accessed July 16, 2020.
2. JAMA. Planning for a COVID-19 Vaccination Program. Published May 18, 2020. Accessed July 16, 2020.
3. Johns Hopkins University; Coronavirus Resource Center. Early Herd Immunity against COVID-19: A Dangerous Misconception. Accessed May 26, 2020.
4. Business Insider. Sweden's 'herd immunity' hopes are fading as only a small fraction of the population has coronavirus antibodies. Published June 21, 2020. Accessed June 29, 2020.
5. MedlinePlus; U.S. National Library of Medicine National Institutes of Health. Vaccines (immunizations). Page last updated: May 7, 2020. Accessed June 4, 2020.
6. Association for Professionals in Infection Control and Epidemiology (APIC). Herd Immunity. Accessed June 4, 2020.
7. STAT News. CDC broadens guidance on Americans facing risk of severe Covid-19. Published June 25, 2020. Accessed June 26, 2020..
8. NBC News. Graphic: Coronavirus deaths in the U.S., per day. Accessed July 16, 2020.
9. JAMA Network. Assessment of Deaths From COVID-19 and From Seasonal Influenza. Published Online: May 14, 2020. Accessed May 27, 2020.
10. Harvard Health Publishing. Coronavirus Resource Center. Updated: June 17, 2020. Accessed June 19, 2020.
11. CNN. What happens if a coronavirus vaccine is never developed? It has happened before. Updated May 4, 2020. Accessed June 1, 2020.
References – Myth #2: Vaccine availability
1. FiercePharma. FDA could approve 'at least one' COVID-19 vaccine before election: analyst. Published June 22, 2020. Accessed June 25, 2020.
2. Business Insider. Scientists are racing to create a coronavirus vaccine that can halt the pandemic in its tracks. Here are the top 3 candidates from Moderna, Pfizer, and AstraZeneca aiming to be ready this fall. Published July 1, 2020. Accessed July 5, 2020.
3. Reuters. Vaccine makers face biggest medical manufacturing challenge in history. Published June 25, 2020. Accessed June 25, 2020.
4. Supply Chain Dive. Developing the coronavirus vaccine supply chain. Published June 16, 2020. Accessed June 25, 2020.
5. Washington Post. Decades of research on an HIV vaccine boost the bid for one against coronavirus. Published July 14, 2020. Accessed July 19, 2020.
6. Market Watch. Race for a COVID-19 vaccine has drug makers scaling up manufacturing — before one is developed. Published June 29, 2020. Accessed July 17, 2020.
7. New England Journal of Medicine. Perspective: Developing Covid-19 Vaccines at Pandemic Speed. Published online March 30, 2020. Accessed June 11, 2020.
8. Duke University. COVID-19 Vaccine in 2020 highly unlikely, experts caution. Published June 24, 2020. Accessed July 2, 2020.
9. Biopharma Dive. A coronavirus vaccine may arrive next year. 'Herd immunity' will take longer. Published May 4, 2020. Accessed May 26, 2020.
10. The STAT Trade Times. Air logistics for Covid-19 vaccine. Published June 27, 2020.
11. Axios. How the U.S. might distribute a coronavirus vaccine. Published May 29, 2020. Accessed July 3, 2020.
12. European Pharmaceutical Review (EPR). The extra mile: preparing a supply chain for a COVID-19 vaccine. Published June 29, 2020. Accessed July 3, 2020.
13. U.S. Department of Health & Human Services. Fact Sheet: Explaining Operation Warp Speed. Published June 16, 2020. Accessed July 4, 2020.
14. Science. COVID-19 and flu, a perfect storm. Published June 12 2020. Accessed July 16, 2020.
References - Myth #3: Return to normal life
1. FiercePharma. FDA could approve 'at least one' COVID-19 vaccine before election: analyst. Published June 22, 2020. Accessed June 27, 2020.
2. New York Times. The Race to Develop a Covid Vaccine. Published June 22, 2020. Accessed June 22, 2020.
3. VOX. Why a vaccine may not be enough to end the pandemic. Published June 3, 2020. Accessed July 17, 2020.
4. STAT News. The world needs Covid-19 vaccines. It may also be overestimating their power. Published May 22, 2020. Accessed May 25, 2020.
5. Organisation for Economic Cooperation and Development (OECD). Health at a Glance 2019 : OECD Indicators; Vaccinations. Accessed July 6, 2020.
6. JAMA News. Planning for a COVID-19 Vaccination Program. Published May 18, 2020. Accessed July 17, 2020.
7. AP-NORC Center. Expectations for a COVID-19 Vaccine. Poll conducted May 14-18, 2020. Accessed July 23, 2020.
8. Association for Professionals in Infection Control and Epidemiology (APIC). Herd Immunity. Accessed June 4, 2020.
9. Centers for Disease Control and Prevention. Flu Vaccination Coverage, United States, 2018–19 Influenza Season. Posted online September 26, 2019. Accessed July 6, 2020.
10. National Foundation for Infectious Diseases. Influenza Vaccination: Protecting Yourself by Protecting Your Community. Posted February 12, 2018. Accessed July 7, 2020.
11. Centers for Disease Control. Similarities and Differences between Flu and COVID-19. Page last reviewed: July 10, 2020. Accessed July 17, 2020.
12. Forbes. Confronting Barriers To Covid-19 Vaccine Acceptance. Published May 28, 2020. Accessed July 21, 2020.
13. Population Reference Bureau. Fact Sheet: Aging in the United States. Posted July 15, 2019. Accessed July 21, 2020.
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This article is directed solely to its intended audience about important developments affecting the pharmacy benefits business. It is not intended to promote the use of any drug mentioned in the article and neither the author nor OptumRx has accepted any form of compensation for the preparation or distribution of this article.
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