COVID-19 Vaccine Update #3: The Delta Variant and the Road Ahead

With the Delta Variant surging in many areas of the country and around the world, new questions have emerged about the vaccines, what a “breakthrough” infection is and the role of masks, among others. I wanted to provide an update to my first and second blog posts with answers to the latest questions I’m hearing from patients and families.

1. Why is there another surge in COVID-19 cases?

Unfortunately, the COVID-19 pandemic continues despite the introduction of several effective vaccines. There are several reasons for the new surge of COVID-19 infections. The emergence of coronavirus variants has posed challenges. Not only are these variants much more contagious than the original virus, but the vaccines are also less effective in preventing symptomatic infection. Fortunately, vaccinated individuals with COVID-19 are still much less likely to become seriously ill, get hospitalized, or die. Coronavirus variants might be prevented if more people are vaccinated, but global vaccination rates continue to be very low. In North Carolina, less than 50% of the eligible population have been fully vaccinated. Since unvaccinated individuals are more likely to get COVID-19, low vaccination rates are significantly contributing to this surge in new COVID-19 cases. In addition, less mask wearing, less social distancing, and more travel are increasing exposure to the virus, leading to outbreaks in both vaccinated and unvaccinated people. As COVID-19 continues to spread, vaccination and behaviors to avoid infection continue to be our best defense.

2. What is the Delta variant and why are coronavirus variants appearing?

Viruses, by their nature, mutate and change over time. Some of these mutations make the virus more contagious. The more contagious variants quickly become the dominant strain causing infections around the world. As the coronavirus changes, it can also evade some of the immune response produced by vaccination. This is why lower vaccine efficacy is observed with variants compared to the original virus. In some cases, variants may also be associated with more serious illness. Fortunately, even with lower efficacy, the vaccines still provide significant protection, including a lower risk of serious illness, hospitalization, and death. Although the coronavirus mutates more slowly than other viruses, we will continue to see variants emerge during the pandemic.

3. Why do “breakthrough” COVID-19 infections occur?

Vaccinated individuals can still develop COVID-19. When this occurs, it is called a “breakthrough” infection, since the vaccine did not protect against symptomatic COVID-19. Although COVID-19 vaccines have shown to be highly efficacious, no vaccine provides 100% protection. Vaccine effectiveness is lower with the coronavirus variants, but it is important to remember that the overall effectiveness continues to be quite high, especially for preventing serious illness and death. The other concern is that immunity from the vaccines decreases over time, making it more likely that a vaccinated person could get COVID-19. This has been demonstrated with lower levels of protective antibodies many months after vaccination. Although antibodies are one measure of the immune response, there are also immune cells, called B-cells and T-cells, which provide important protection after vaccination but are more difficult to measure. This means that waning antibodies are not the whole story, and that vaccines offer some degree of protection from COVID-19 many months after vaccination. As mentioned in a previous post, being vaccinated does not make you invincible. Instead of armor, think of the vaccine as a safety net. If you continue to practice safe behaviors, you are less likely to be exposed to the virus. If you happen to be exposed to coronavirus despite your best efforts, the vaccine will prevent serious illness.

4. Why is the CDC now recommending wearing masks indoors for both vaccinated and unvaccinated people?

It is confusing to hear changing recommendations from public health officials. Previous recommendations stated that vaccinated individuals didn’t need to wear masks when associating with other vaccinated individuals. Public health officials even gave the impression that vaccinated individuals could now resume a “normal” life. This was certainly great news and was supported by data that vaccinated people were strongly protected by the vaccine and unlikely to transmit the virus. Unfortunately, circumstances have changed. The emergence of variants has undermined vaccine protection. In addition, new data shows that high levels of variant virus are shed from vaccinated individuals when they have COVID-19. This finding is consistent with epidemiological data showing that vaccinated individuals with COVID-19 can still infect other people. Although wearing a mask can protect a person from COVID-19, perhaps the more important reason to wear a mask is to protect other people from infection.

5. Will vaccinated individuals need an additional (booster) dose of the COVID-19 vaccine?

Most vaccine experts agree that we will need booster doses of the COVID-19 vaccine at some point in the future. This would be a 3rd-dose of the Pfizer and Moderna vaccines, or a second dose of the Johnson & Johnson vaccine. There are really two reasons a booster will be necessary. First, the immune response slowly fades after vaccination. This waning immunity can be “boosted” with another shot. Second, the emergence of variants likely means that the vaccines will need to be adjusted in order to re-educate our immune systems to fight the mutating virus more effectively. This booster “tutorial” will hopefully provide higher efficacy of the vaccine for coronavirus variants. However, we don’t know yet when a booster will be necessary. There is data to support boosters in immunocompromised individuals who did not respond well to the initial vaccine series. Therefore, it is likely that select groups of people will get booster shots first. It is important to note, however, that we still have many people who haven’t been vaccinated or who are not fully vaccinated. Finally, there is tension between the need for boosters and the need to vaccinate more people around the world, especially in developing countries. Since a pandemic is a global health problem, vaccinating as many people as possible will prevent new variants and eventually end the pandemic.

6. Why are health care systems, government, and other employers requiring COVID-19 vaccination for their employees?

Within the medical community, there is an acknowledgment that the COVID-19 vaccines are safe and effective. Vaccination is an important way to protect both patients and employees during this pandemic. Therefore, vaccination is being mandated by many healthcare systems. This is very similar to mandates for healthcare workers to receive influenza vaccination and hepatitis B vaccination, unless there is a specific medical or religious exemption. Government and private industry also view vaccination is a way to protect their workforce. A sick workforce impairs productivity and ultimately increases healthcare expenditures for employers. Current legal opinions and a statement from the U.S. Equal Employment Opportunity Commission provide support for employer vaccine mandates.

7. Why aren’t more people getting vaccinated?

Vaccine hesitancy is one of the most serious threats to public health. We are fortunate to have access to a safe and effective vaccine across the U.S. with no direct cost to the individual, yet many Americans choose not to get vaccinated. The vaccines were not rushed; no corners were cut in the research or development. The authorization of the vaccine by the FDA was based on sound science from properly conducted clinical trials. Since receiving Emergency Use Authorization by the FDA, the administration of millions of doses continues to demonstrate the safety of theses vaccines. Serious adverse events after vaccination continue to be extremely rare and are far outweighed by the numerous lives saved from vaccination. Most side effects from the vaccine are mild and short in duration. These reactions pale in comparison to the serious illness associated with COVID-19. Unfortunately, medical misinformation and political extremism continue to dominate across social media. Incentives, employer mandates, and the anticipated FDA approval of the vaccines will likely nudge the vaccination rates a little higher, but probably not to the level that is required for herd immunity. Education and role modeling continue to be important strategies to combat misinformation and hesitancy. Unfortunately, unvaccinated individuals will continue to be the predominant group getting sick, being hospitalized, and dying from COVID-19.

8. Should individuals who have had COVD-19 still get vaccinated?

Yes! The immune response from COVID-19 can vary greatly and does not necessarily confer long-term protection from re-infection with the coronavirus. However, vaccination has been associated with a strong immune response after recovering from COVID-19. Research has demonstrated that specific immune cells, called T-cells and B-cells, are stimulated by the vaccine and will likely provide long-term protection from COVID-19.

9. Is influenza vaccination still recommended this year?

Yes! Although rates of influenza were low last year when mask wearing and physical distancing limited spread of many respiratory viruses, the influenza virus continued to circulate and is expected to cause illness during this next flu season. It might even return with a vengeance, especially as children return to classrooms this fall. Since influenza can cause serious illness and death for older adults, annual vaccination is important. Influenza vaccines (flu shots) should be widely available across the country starting this fall and are strongly recommended.

10. Is there an end in sight for the COVID-19 pandemic?

We do not know how quickly the COVID-19 pandemic will end. Much depends on getting as many people vaccinated as possible. Global vaccination continues to be challenging, especially in developing countries. Inevitably, hospitalizations and deaths will continue among the unvaccinated. Even if we can achieve very high rates of vaccination in the U.S., it is likely that cases of COVID-19 will continue to be identified in localized outbreaks for many years. We may see modified vaccines for the variants and booster doses over the next year, but we will probably face the same challenges of vaccine hesitancy. The end of the pandemic really takes a global vaccination approach combined with our individual willingness to get vaccinated and continue practicing safe behaviors.

Anthony J. Caprio, MD, is medical director at Sharon Towers and geriatrician at Atrium Health. The opinions expressed by Dr. Caprio in this article are his own and not necessarily those of Atrium Health.

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