COVID Update: U.S. Exceeds 400 Million Vaccine Doses and Waning Efficacy

Coronavirus Origins

Between the numerous COVID-19 vaccines and several new antiviral drugs, it would appear that the tools to end the COVID-19 pandemic are within reach. Here’s a look at some of the top stories.

Merck/Ridgeback and Pfizer’s Antiviral Drugs: What We Know

Merck and Ridgeback Therapeutics’ molnupiravir was authorized in the U.K. to prevent and treat COVID-19 in early November. In studies, it decreased COVID-19 hospitalizations by 50% and prevented deaths completely. It is under review in the U.S., with a decision expected by the end of the year. About two days later, Pfizer announced that its antiviral, Paxlovid, decreased the risk of hospitalization or death by 89% compared to placebo in high-risk adults who were not hospitalized for COVID-19. Pfizer halted the study and planned to request Emergency Use Authorization (EUA) from the FDA. Both drugs are given in pill form and would allow people at high risk of the severe disease or diagnosed with COVID-19 to take the medicines at home to prevent the worst of the disease. However, the data provided to date on both drugs came in press releases, not peer-reviewed scientific articles. Below is a brief overview of what is known.

The Pfizer pill was given within three days of the patient’s first symptoms. Patients who received it within five days saw an 85% improvement in hospitalization or death rates compared to placebo. Merck-Ridgeback’s was given within five days. The companies haven’t shared data on patients who received molnupiravir within three days of symptoms. Both drugs were 100% effective in preventing death from COVID-19 no matter when the patients started receiving the pills. Merck-Ridgeback’s trial observed eight deaths in the placebo group, and Pfizer reported 10 in the placebo group, none in the cohorts receiving the drugs. Side effects were similar for both drugs, which were similar to those seen in the placebo cohorts. No details about the side effects have been released by either company. Both drugs are given twice a day for five days, a total of 10 pills. Pfizer’s drug is co-administered with another antiviral called ritonavir.

The studies were performed on patients at high risk of complications from COVID-19 who had not been vaccinated. It’s an open question on whether the drugs would be authorized for vaccinated people who suffer breakthrough infections because it hasn’t been tested in that population. Pfizer is conducting a trial of the drug that includes people vaccinated with data expected in 2022.

U.S. Has Given More than 400 Million Vaccine Doses

According to the U.S. Centers for Disease Control and Prevention (CDC), as of Sunday morning, November 14, 2021, the U.S. had administered 440,559,613 doses of COVID-19 vaccines. Of them, 195,120,470 people had been fully vaccinated and 226,607,653 had received at least one shot. To date, approximately 29.3 million have received a booster shot of one of the three vaccines available in the U.S., Pfizer-BioNTech, Moderna, or Johnson & Johnson.

In Comparative Study, Pfizer-BioNTech Shot Created Most Antibodies

In a study published in Cell Host and Microbe comparing four COVID-19 vaccines, the Pfizer-BioNTech shots created the strongest immune response. The study compared the Pfizer-BioNTech, AstraZeneca-Oxford, Sputnik V and Sinopharm vaccines. China’s Sinopharm appeared to be the weakest, allowing the most so-called breakthrough infections—cases of COVID-19 after vaccination. Of the four, the Sinopharm and Sputnik V vaccines generated “relatively low” antibody concentrations, AstraZeneca-Oxford was intermediate, and Pfizer-BioNTech was the highest.

COVID-19 Vaccine Efficacy Wanes, but How Important Is It?

Studies show that the efficacy of COVID-19 vaccines drops over time. For example, a recent study showed that the Pfizer-BioNTech vaccine was about 90% effective at preventing symptomatic infection two weeks after the second shot but dropped to 70% after five months. This has been the argument for providing booster shots. However, immunologists and vaccine experts say that doesn’t mean the vaccines are no longer working. Other studies demonstrated that the vaccines are still more than 50% effective at preventing infection, which is the threshold the U.S. Food and Drug Administration (FDA) had initially set in 2020 for authorization.

The diminishment is also based on antibody levels but doesn’t consider memory T and B cells, which offer long-term protection. Although protection does appear to drop over time, the vaccines appear to be very effective at preventing hospitalization and death.

“The main objective of the COVID vaccine is to prevent severe disease and death, and they are still doing a good job at that,” said Melissa Higdon, a faculty member at the Johns Hopkins Bloomberg School of Public Health.

However, Higdon thinks the drop in protection against infection will have an effect. “With true declines in vaccine effectiveness, we’ll likely see more cases overall.”

Non-Whites At Higher Risk of COVID Infection and Severe Infections, Lower Deaths

A meta-analysis and review of data on 4.3 million patients in the U.S. found that African Americans, Hispanics, and Asians were at higher risk of COVID-19 infection and severe disease than whites, but were less likely to die of it. The research was published in JAMA Network Open and attempted to find out the link between socioeconomic determinants of health and racial disparities in COVID-19 outcomes. The researchers at the University of California in San Diego evaluated data from January 1, 2020, to January 6, 2021, before the Delta variant took over in the U.S.

Flu and COVID-19 Vaccines Safe to Be Given Simultaneously

A U.K. study published in The Lancet found that it was safe to co-administer flu and COVID-19 vaccines. The study involved 679 patients at 12 U.K. sites. The patients received one of three inactivated age-appropriate seasonal flu vaccines and either the second dose of the Pfizer-BioNTech or AstraZeneca-Oxford COVID-19 vaccines or a placebo. Most systemic adverse reactions were mild to moderate. There was one serious adverse event, hospitalization with severe headache, that was believed to be related to the intervention. The antibody responses generated for both the flu and COVID-19 were considered to be effective.

NanoViricides Completed Studies of Oral Gummies and Inhalation Formulations of COVID-19 Drug

NanoViricides, based in Shelton, Ct., announced that it has developed oral gummies formulations of its Pan-Coronavirus COVID-19 Drug Candidate NV-CoV-2 for non-hospitalized patients. It has also developed formulations for direct inhalation into the lungs for severely ill people and hospitalized with the disease. In animal models, the formulations demonstrated strong safety. No hypersensitivity or adverse reactions at the injection site or any other adverse events were seen in multiple animal studies.

“We believe that NV-CoV-2 and NV-CoV-2-R would be highly effective drugs against SARS-CoV-2, based on multiple animal studies data,” said Dr. Anil Diwan, chairman and president of NanoViricides. “We believe that NV-COV-2 may help end the pandemic if it is shown to be effective in human clinical trials.”

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