Ask Dr. Halverson: Coronavirus vaccines: Encouraging news, significant challenges

web 4 17 Halverson photo
By Dr. Jim Halverson
As COVID-19 cases surge, with little relief in sight, the world got good news Nov. 9. Pfizer and its partner, the German company BioNTech, announced preliminary results that suggest their vaccine was more than 90 percent effective. However, there is still much we need to know about how well the vaccine works. Here is the current status on vaccines and some of the significant challenges that remain in the months ahead.
Pfizer’s good news
Pfizer and BioNTech partnered in March to develop a vaccine for COVID-19.  Twenty vaccine candidates were initially tested. After early human trials, the researchers determined that two vaccine candidates produced the most robust immune responses. They chose the vaccine that had shown fewer side effects to start a Phase 3 trial in late July with 30,000 volunteers in the United States, Argentina, Brazil and Germany. In September, they expanded their U.S. trial to 44,000 participants. In October, they gained permission to start testing the vaccine on children as young as 12 — the first American trial to do so.
Pfizer has taken great care to increase the confidence of a wary public in their vaccine’s safety. It led the effort to get major drug companies to publicly pledge that any coronavirus vaccine would stand up to public scrutiny. It also took the highly unusual step of publicly releasing its trial blueprints, known as protocols, revealing typically secret details about how it was evaluating its vaccine.
The trial’s protocol allowed four interim analyses, early looks that would give an outside board of experts a chance to identify safety concerns and assess whether the vaccine was working. The first analysis, having just been completed on Nov. 8, found that the vaccine was more than 90 percent effective in preventing COVID-19 among trial volunteers who had no evidence of prior coronavirus infection. Significant immune response was present within four weeks of the first of the two vaccine doses given three weeks apart. In addition, no serious safety concerns were found.
Pfizer plans to ask the Food and Drug Administration for emergency authorization of the vaccine later this month, after it has collected the recommend two months of safety data. By the end of the year, it will have manufactured enough doses to immunize 15 million to 20 million people.


Other promising vaccines
Eleven other vaccines are in late-stage (phase 3) trials across the globe. The fact that Pfizer and BioNTech have gotten encouraging results is making experts optimistic about the entire field. Pfizer’s vaccine causes our bodies a make a viral protein called a spike protein that distinguishes the novel coronavirus from other coronaviruses. A number of other vaccines deliver the spike protein, or just a fragment of it, into the body, that triggers our immune system to produce antibodies and T cells to protect us from the virus.  Since the spike protein is prompting such a good immune response, all of these vaccines might also deliver encouraging results in the months to come. Widespread success of coronavirus vaccines would be a huge boon to the world’s health because Pfizer and BioNTech alone cannot meet the full demand of potentially vaccinating several billion people.
Three additional vaccines in phase 3 trials in the United States could be given approval by the FDA in the very near future. One is Moderna’s messenger RNA vaccine, which is very similar to Pfizer’s. On Nov. 16, Moderna announced a 94.5% efficacy in its first interim phase analysis. This vaccine has the extra benefit of being able to be stored at refrigeration temperatures common to many physician’s offices, pharmacies and hospitals. In addition, AstraZeneca’s vaccine, made in collaboration with the University of Oxford, and Johnson and Johnson’s vaccine are nearing completion of phase 3 trials. Unlike other vaccines in phase 3 trials, the vaccine by Johnson and Johnson requires only one dose instead of two.
Challenges ahead
Widespread distribution of Pfizer’s vaccine will be a logistical challenge. Because it is made of messenger RNA, the vaccine will have to be chilled to minus 70 degrees Celsius (minus 94 degrees Fahrenheit) until it is ready to be injected. Pfizer has designed a special cooler to transport the vaccine equipped with GPS-enabled thermal sensors. The U.S. government, with the help of Federal Express and other transportation companies, will assist in guaranteeing safe distribution.
After arrival at designated distribution centers, people will be given the vaccine based on a priority system that is still in the development stage. Current recommendations are being created by the Advisory Committee on Immunization Practices, an expert panel that crafts  vaccination guidance for the CDC and by state, local and tribal health authorities who must identify the actual people who fall into the priority groups. 
A consensus has formed that health care personnel should be the first in line to get the vaccine, given their high risk of exposure. Health care workers are defined by ACIP as “paid and unpaid persons serving in health care settings who have the potential for direct or indirect exposure to patients or infectious materials.” This population is estimated at 21 million. Other high-priority groups include adults who have one or more high-risk conditions such as obesity, diabetes and cardiovascular disease, or are 65 and over, including those living in long-term-care facilities. In addition, people in other essential areas, defined as people who “conduct operations vital for conducting critical infrastructure, such as agriculture, transportation, education and law enforcement,” will likely receive higher priority.
Acceptance of the safety of the vaccine and agreeing to be vaccinated are other extremely important components to our success in controlling COVID-19. The most important attribute in a recent Journal of the American Medical Association study was efficacy of the vaccine. Fifty-one percent of study participants indicating they would receive a vaccine with 50% efficacy. Sixty-one percent indicated they would take a vaccine showing 90% efficacy. Even this percentage is far below the estimated 70% of Americans who will need to be vaccinated to provide herd immunity.
Maintaining our patience to continue appropriate preventative measures until we are able to get the vaccine is critically important. Most health officials think an effective vaccine will not be broadly available to anyone who wants it until well into next year. Even when the vaccine or vaccines are widely available, public health measures such as masks, hand-washing and social distancing will be necessary until the public health threat has subsided. We must not let our guard down as case numbers begin to decrease.
Vaccines will bring hope and the first major step toward ending this pandemic. Celebrate the good news as vaccines are approved and made available. Strongly consider the benefit for you and others around you if you take the vaccine. Stay committed, stay optimistic, stay well informed, say safe and stay well.


— Dr. Jim  Halverson is a longtime Ojai physician who writes a weekly column on COVID-19 for the Ojai Valley News.


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