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The “last mile” for COVID-19 vaccines could be the biggest challenge yet


A race to develop a COVID-19 vaccine began almost at the time the genetic composition of the coronavirus was revealed in January.

Already two companies have announced that their vaccines look safe and are 95 percent effective (SN: 18/11/20, SN: 16/11/20). UK government regulators granted permission on December 2 for emergency use of a vaccine made by the pharmaceutical company Pfizer and its German biotechnology partner BioNTech. The first doses could be delivered within days of the announcement. Emergency use authorization and even full approval of vaccines is likely not far off in the United States and other countries.

But another race is just beginning. Ultimately, vaccines will not be truly successful until there are not enough people to stop the spread of the virus and prevent serious illness and death. And that will pose a logistical challenge unlike any other.

In normal times, potential vaccines have only a 10 percent chance of being given from phase II clinical trials, which test for safety, dosage, and sometimes give advice on efficacy, to approval within 10 years, the researchers reported on Nov. 24 in the Annals of Internal Medicine. On average, successful vaccines are needed for four years to move from phase II trials to full regulatory approval.

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Even if COVID-19 vaccines manufactured by Pfizer or the Modern Biotechnology Company are distributed in late December under emergency use provisions – less than a year after clinical trials begin – they may not receive full approval from the Administration. U.S. food and medicine for months, or even years. Still, that action divided by candy to get a vaccine against a disease hitherto unknown is unparalleled.

But while the race to make a COVID-19 vaccine is advancing at a world-record pace, it is far from over, says Robin Townley in Washington, DC, who directs special project logistics for AP Moller-Maersk, a company that handles logistics and transportation supply chain services for companies around the world.

"The vaccine race now is not an out-of-lab race. It's a race for the patient," he says. And the most successful vaccines, Townley says, will be the ones manufactured by the companies that pay the most attention to the last mile of the race.

That last mile: the vaccine journey from, say, centralized distribution centers to clinics, and ultimately to patients, is not a measure of distance. It’s a maze of pothole-strewn regulations and supply chains in which companies must navigate to distribute their vaccine, ultimately to almost everyone on the planet.

The magnitude and intensity of the task ahead is unprecedented, Townley says. "It's the largest product launch in human history."

Managing the last mile

The sheer scale of vaccinating the world is daunting. With most COVID-19 vaccines in development requiring two doses for a full effect, there will be approximately 15 billion doses worldwide.

Control of vaccine release is a key variable – at least as important as vaccine efficacy – in the equation that determines how a vaccine will calm the pandemic, researchers reported Nov. 19 in Health Affairs. The researchers considered different scenarios, calculating the effectiveness of the vaccine, the rate at which people could be vaccinated (depending on both delivery systems and public disposal), and how quickly the virus spreads.

Even a vaccine that is only 50 percent effective in preventing the disease could quell the pandemic if it spreads quickly enough, says study co-author Jason Schwartz, a vaccination policy researcher at Yale School of Public Health. "Application is important."

Creating vaccines is a remarkable scientific achievement, Schwartz says, but the technical and logistical challenges of getting vaccines to go will be as challenging as the scientific problems.

For example, although many of the vaccines on site will require refrigeration, the Pfizer vaccine – the first fully tested vaccine to get permission for emergency use – must be kept especially cold, frozen at -70 ° C. That vaccine requires ultrasonic freezers. or dry ice to refill specialized delivery containers (SN: 20/11/20). The Moderna vaccine should also be frozen, but is stable at regular freezer temperatures.

The vaccines will be transported from Pfizer's "freezer farm" (shown) in Kalamazoo, Michigan, to various locations in the United States. In Europe, similar facilities in Belgium and Germany will manage the distribution and the Belgian site will serve as support for the Michigan site.Pfizer

To get an idea of ​​the task ahead, imagine “putting two iPhones in the hands of every human being on the planet and making sure those iPhones are cold when they get there,” Townley says.

Refrigerated trucks, planes and trains and freezers that can carry such cold goods are not in large quantities. Townley says cold transportation is also needed to move bacon, avocado, and many other foods and medications, such as insulin. “Normal systems are not built to take on this big challenge in this short amount of time,” he adds.

As a result, compensation will have to be made. Either distributors will not be able to ship any other temperature-controlled cargo or will have to add more cold-carrying capacity, which is expensive.

Much of the need for cold transportation is seasonal, as is the avocado season in South Africa and Mexico. "If the vaccination season comes to South Africa at the same time as the avocado season (and) there's not much capacity to carry avocados," says Townley, "what does that do to South Africa's economy?"

Mei Mei Hu, co-founder and CEO of Covaxx, a Hauppauge, New York-based company working on its own COVID-19 vaccine, will find it quite difficult for many U.S. locations to manage the Pfizer cold vaccine. . And “if it’s difficult in the United States, it will be virtually impossible in most emerging markets,” such as Central and South America and many parts of Africa, she says.

Even the usual freezers, such as those needed to store Moderna’s vaccine, can be a challenge in some areas. “There are a lot of places where you can’t have a cold coke,” Hu says.

Keeping it cold

Pfizer has created special shipping containers, nicknamed pizza boxes for similar food delivery containers, that can be refilled with dry ice to keep the company’s vaccine cold in transit and for short-term storage. The U.S. government has told states it will send a dry ice refill with each vaccine shipment, says Kurt Seetoo, the immunization program manager at the Maryland Department of Health in Baltimore.

But that recharge won’t last long, so suppliers will have to find local sources of dry ice, which can be difficult in rural areas. Maryland is working with local contractors to ensure there is a ready supply of dry ice when needed, Seetoo says.

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Pfizer assured U.S. health officials that their vaccine can be kept for up to 15 days in their pizza boxes with dry ice refills every five days and then spend another five days in the refrigerator before it goes bad, Seetoo says. That gives officials about 20 days to distribute the vaccine once they receive it.

Still, dry ice is sublimated or converted directly into carbon dioxide gas. Smoke can build up and suffocate people if there is not enough ventilation, which could make transporting and storing vaccines cooled with dry ice a problem.

One solution is to use devices developed to transport cells between labs or to transfer temperature-sensitive drugs to clinics, such as those used in cancer or gene therapies, says Dusty Tenney, executive director of Stirling Ultracold, a company that makes portable freezers that go up to –80 ° C.

Stirling's portable freezers – which look like high-tech versions of beach refrigerators – are being rolled out to get COVID-19 vaccines from "freezer farms," ​​where vaccines are stored after they leave production lines, clinics and more. distribution sites.

These freezers are just one link in a “cold chain” needed to keep vaccines fresh and effective. But the chain is fragile. The World Health Organization estimates that about 2.8 million vaccine doses were lost in five countries in 2011 because the cold chain was broken. This includes losses in countries like Nigeria, where 41 percent of refrigerators did not work, and Ethiopia, which had about 30 percent of its cold chain equipment. Losing millions of doses of COVID-19 vaccines can be disastrous for controlling the pandemic.

Dosing dilemma

In the United States, another hurdle is that every state is unsure of how many vaccines it will receive from the federal government, Seetoo says. This makes it difficult to determine how many doses the state will receive for health workers and people in long-term care homes who will be the first in line to be vaccinated (SN: 01/12/20).

And the two-dose requirement for most COVID-19 vaccines adds to supply problems, says Christine Turley, pediatrician and vice president of research for Atrium Health Levine Children's Hospital in Charlotte, NC Unless doctors say. pharmacies and other providers are confident that. ”You will have a steady supply of vaccines, they will have to save half a shipment to give people a booster three weeks to a month after the first shot.

“If I vaccinate people and I can’t provide a second dose, that doesn’t fulfill a moral and ethical obligation,” Turley says.

Another potentially daunting logistical challenge is tracking who has been vaccinated, who got the vaccine (both doses must come from the same company) and when people need a second dose. The databases used to manage patient data or to order and send medical supplies are not well integrated between vaccine providers and local, state and federal government agencies, which could lead to confusion, says Pouria Sanae, executive director of ixlayer, a company that provides logistics. services for COVID-19 testing and vaccination centers. Existing databases may need to be strengthened and given new ways to manage information, he said.

worker loading COVID-19 vaccine vials into containersA worker loads COVID-19 vaccine jars from Pfizer and BioNTech into specialized containers, nicknamed pizza boxes, which are loaded with dry ice to keep the vaccines at –70 ° Celsius for short-term transport and storage.Pfizer

And not only will digital infrastructure be important. Physical spaces will be needed to administer vaccines and their multiple doses to as many, many people as quickly and efficiently as possible.

For comparison, Sanae points out that the demand for widespread testing of COVID-19 initially surprised many people. “If we went back in January and told you we’d take samples in a parking lot, you’d probably laugh at me,” he says. But that’s what it can take for vaccines to be distributed as widely as the tests. It provides for all schools, governments, and community testing centers to become vaccination clinics, along with medical offices, pharmacies, hospitals, and other clinics.

Logistical nightmare

Finally, it is not just vaccines that need to be deployed without problems. Suppliers of glass jars containing vaccines need to make sure they have enough surgical-grade sand to manufacture them. Nurses who receive vaccines need alcohol wipes, syringes, needles, masks, and gloves, some of which are scarce in some places. Managing all that logistics is a sticky proposition, especially on the scale needed to immunize the world against COVID-19.

“Logistics is moving forward,” Turley says. From Borneo to Paris to Charlotte, North Carolina, the best way to distribute vaccines is a problem people are facing everywhere, she says. "The only consolation is that everyone is dealing with this, and that's not a consolation for any of us."

Even if everything works smoothly and distribution occurs as quickly as the initial development of vaccines, everything could be in vain if people do not take other measures, such as the use of universal masks and social distancing, which can help slow the spread of the virus. .

Schwartz, the Yale vaccination policy researcher, and colleagues took the spread of the virus into account when making their calculations. If things continue as they have in recent weeks, with more than 150,000 new cases of coronavirus and about 1,500 deaths (about one per minute) reported daily in the United States, vaccine distribution would have to move lightning to prevent millions of deaths. “If we’re in that (high level of transmission), even a highly effective vaccine will struggle to make a dent in the pandemic’s trajectory,” Schwartz says.

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