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Ask Dr. Halverson: Promising progress toward COVID-19 vaccine

web 4 17 Halverson photo
By Dr. Jim Halverson
Bringing the pandemic to an end depends on the development, distribution and administration of a safe and effective vaccine (or vaccines) against the SARS-CoV-2 virus, which causes COVID-19. Since my July 3 column in the Ojai Valley News, significant progress has been made on both the development and distribution front. I now am convinced that we will know by late 2020 which vaccines are safe, how effective they are, and which ones should be used to vaccinate our U.S. population in 2021. 
HERD IMMUNITY
First, a short reminder on the importance of herd immunity. This occurs when enough people in a defined population have developed immunity to an infectious disease so that the risk of further community spread of the disease is eliminated or significantly reduced. For the SARS-CoV-2 virus, this percentage of the population is estimated at 60% to 70%. 
Immunity is either achieved by being exposed and infected, so protective antibodies develop that protect a person from developing another infection. This immunity also makes them unable to pass that infection on in the future. Immunity also happens if a person is vaccinated and develops those same protective antibodies. Current estimates are that 5% to 10% of our population has developed these antibodies through symptomatic or asymptomatic infection. Therefore, vaccinations are needed to give adequate immunity to our population, which then will significantly slow down and, hopefully, stop the spread of COVID-19 in the United States.

 

CURRENT STATUS 
Thirty-two vaccines are now in human trials around the world, 16 more than in early July. Eight of those are in phase 3 trials, the final phase before approval. In this phase, scientists give the vaccine to thousands of people of all ages, including those with underlying health conditions, and children, with parental consent.  Immune response is measured over time and compared both to a placebo group and to known immune response of people who have been infected and have recovered. The U.S. Food and Drug Administration said in June that a vaccine would have to protect at least 50% of vaccinated people in these trials to be considered effective.
Potential side effects are reported on a regular basis by the participants in both the vaccinated and placebo group. Phase 3 trials are large enough to reveal evidence of relatively rare side effects that might not have been detected in smaller phase 1 and phase 2 trials.
Many countries are involved in these phase 3 trials. In the United States, Moderna, in collaboration with the National Institute of Health and Pfizer, in collaboration with German company BioNTech are coordinating trials with 30,000 people each. Both have currently enrolled more than 12,000 people and are expected to complete enrollment by late September. 
In addition, both have received significant funding from the U.S. government to begin production of the vaccines now so that administration of their vaccine can begin if they receive FDA approval. The British-Swedish company, AstraZeneca, and the University of Oxford have a vaccine in phase 3 trials in England, India, Brazil, South Africa and the United States. Both the U.S. government and the European Union have given significant financial support to begin production of the vaccine. 
These trials are being done with the utmost of care and meticulous monitoring of participants. In the Pfizer trial, one of the volunteers is Dr. Victoria Smith, a family physician near New Orleans, Louisiana. For her, COVID-19 is personal. “I want to be part of the solution,” she said. She has lost three patients to the virus. In late July, she became one of the first of the 30,000 participants in the phase 3 trial, receiving her first injection July 29 and second injection Aug. 19. As the study is double-blinded, she does not know if she is receiving the vaccine or a placebo. She is required to take her temperature and report any symptoms on a phone app to the trial coordinators daily for a week after each injection and then weekly for the next two years. 
Frequent blood tests are taken to measure for any adverse effects and to monitor immune response. She is proud to be part of the trial and, being a Black physician, she hopes to be a role model to encourage other minorities to sign up to participate. Her efforts and those of other minority participants are working. Nearly 20 percent of both the Moderna and Pfizer U.S trials are Black, Hispanic or Native Americans, representing three groups that have been affected disproportionately in our country.
REASON FOR OPTIMISM
Early results are very encouraging. Thus far, participants in the vaccine group have shown good immune response in development of neutralizing antibodies in amounts equal to or greater than antibody levels found in COVID-19 survivors. In addition, side effects have been relatively mild with injection site tenderness, low-grade fever, headache and fatigue being among the most common.  
CONCLUSION 
The process of approval for COVID-19 vaccines in the United Stated is extremely demanding and being done with the utmost care and oversight. More is being learned daily about the disease this coronavirus causes and possible short and long-term health consequences. Similarly, more is being learned daily about how vaccines in trials can help to prevent this disease. Questions remain that only further studies can answer. What percentage of vaccine recipients will develop immunity?  How long will immunity last?  How many of us will get the vaccine? 
Ultimately, all of you will be given this choice. For those of you who are uncertain about vaccination benefits, I hope you will consider how individuals like Dr. Smith and tens of thousands of others have willingly volunteered to help us get the answers we need. Also, please consider that your actions will not only protect you, but will help to protect the health of all of us.
Stay informed. Stay positive. Stay committed. Stay safe. 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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