Nearly a year into the Covid-19 pandemic, a picture of the other side is emerging. There has been positive news from leading vaccine manufacturers and they are beginning to analyze phase III clinical data, an important milestone which could tell researchers about whether they are safe and effective.
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But to distribute those vaccines, the US must undertake the most logistically difficult vaccination campaign in history, with a hesitant and weary public, and at least one vaccine with unprecedented storage requirements.
The cause for optimism is real – but so are the logistical challenges that lie ahead.
Transparency and trust
One of the biggest hurdles any vaccination campaign will face is gaining public trust, including among healthcare workers who will be asked to take the vaccine first.
“One of the really difficult challenges we have before us is getting people to trust the vaccine,” said Dr Michael Osterholm, an epidemiologist at the University of Minnesota who was recently tapped to serve on the Biden-Harris administration’s coronavirus advisory board.
Pfizer must submit the data on its vaccine to the US Food and Drug Administration for approval, but another important step will be publication in an independent, peer-reviewed scientific journal, and continued transparency about its safety and efficacy.
The broader public will also need information on how the vaccine is performing, and consistent messaging from scientists. This will be a challenge amid a change in leadership in the White House, after almost a year of Covid misinformation perpetuated by Donald Trump, and in the era of audiences fractured by social media.
“This is our best way out of this pandemic, so we want to recommend and encourage our community members to take the vaccine,” said Dr Umair Shah, executive director of the Harris county health department in Texas.
“What would be the worst is a vaccine that’s safe, a vaccine that’s effective, a vaccine that’s distributed, and vaccine systems now able to get vaccines in the arms of people – and people just don’t take it,” Shah said.
Extreme storage requirements
As public health authorities work to regain public trust, they must also tackle the unprecedented cold storage requirements of the leading vaccine candidate from Pfizer and German company BioNTech.
This vaccine uses technology called a messenger RNA platform, which uses the genetic material of Covid-19 to invoke an immune response. The vaccine leads the pack because it is the quickest to manufacture.
But speed of manufacture is offset by complicated delivery. Pfizer’s vaccine needs to be stored at an unprecedented -94C (-137.2F) a temperature met only with the coldest deep freezers.
Pharmacies do not have freezers this cold, because no approved drug has ever needed to be held at this temperature. Only large medical centers, universities and perhaps some public health departments will probably have such deep freezers.
To get around this, Pfizer has developed a reusable, suitcase-sized shipping container where 975 doses of the vaccine are kept on dry ice. The vaccine is stable for 10 days from the point of departure in this case. If more dry ice can be secured, then the vaccine can be kept in the case for another 15 days.
“The clock starts well before you actually receive the product,” said Soumi Saha, an attorney, pharmacist and vice-president of advocacy at the healthcare logistics company Premier Inc.
Dry ice is considered a hazardous material, so it cannot be shipped by air or sea. It must be transported by ground, posing potentially serious challenges for rural areas where several days of vaccine viability could be lost in transit.
During this time, the case can only be opened twice a day for one minute per opening. Healthcare workers will need to take out an appropriate amount of vaccine only twice a day, meaning carefully calibrating between taking out too little and risk sending patients home, and taking out too much and risk wasting very limited doses.
The nursing shortage
The first on the list to receive the vaccine are healthcare workers, but herein too is a challenge. There is commonly a nursing shortage in the US, but healthcare facilities are facing more extreme staff shortages because of the enormous spread of Covid-19 across the US.
In many cases, the same workers who test the public will have to turn around and vaccinate fellow workers. Those doses will need to be metered out, because potentially flu-like side-effects from the virus could sideline some. For that reason, a hospital could not vaccinate its entire intensive care unit at once.
“If you have a staff of 25,000 you have to vaccinate, it’s not going to be easy to find the staff to do that,” Saha said.
It is estimated that each worker performing vaccinations can only perform six vaccinations an hour, according to Saha. Those workers will also need to be trained to handle the extreme storage requirements of the vaccine, including how to defrost, dilute and administer it.
Then, healthcare providers have to get workers to return for a second dose of the vaccine, which all but one vaccine candidate requires. Tracking who received which vaccine and when, will be a major data undertaking.
Further, the current vaccine distribution plan provides doses based on state population, not based on the number of health workers who will first be vaccinated. That means some states could have a surplus of vaccines while others have a deficit.
Approving new vaccines
The world needs multiple vaccines to be approved to even begin to meet demand. But approving multiple vaccines adds to the complexity of the delivery effort. Healthcare providers will need to track who received which vaccine and when, to ensure people are protected.
The goal is for all Americans to have access to a vaccine “within 18 months from initial vaccine approval”, said Saha.
For example, the first approved vaccine may not be safe and effective for all people. Vaccines are only beginning to be tested in children, and some vaccines may not be safe and effective in people older than 65.
The challenges are vast, but there is hope
As vaccine infrastructure is developed, more advanced versions of vaccines could reduce the logistical challenges of distribution. Already, Pfizer is working on a powdered version of its vaccine in hopes of reducing cold storage requirements in 2021.
Further, not all vaccine candidates require cold storage at the same extreme temperatures described here. The other leading candidate from Moderna and the National Institute of Allergy and Infectious Diseases could be kept at -20C, or roughly the temperature of an existing adult shingles vaccine.
And, at least for now, the best defense against Covid-19 remain social distancing, mask-wearing and hand-washing.
“We may be tired of this virus but this virus is not tired of us,” said Shah. “I hope that on the road ahead that we remember a public health crisis requires a public health response.”
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