FAU Expert Answers Questions about the Delta Variant and Vaccines

COVID-19, Delta Variant, Vaccines, Public Health, Public Safety, Frequently Asked Questions, Florida, CDC, FDA, Pandemic

Data from the U.S. Centers for Disease Control and Prevention (CDC) suggest that currently more than 80 percent of cases of COVID-19 are the Delta variant.

By gisele galoustian | 8/4/2021

Florida Atlantic University’s Joanna Drowos, D.O., M.P.H., M.B.A., associate chair of the Department of Integrated Medical Science, an associate professor of integrated medical science, and a practicing physician at the Marcus Institute for Integrative Health at FAU Medicine, within  the Schmidt College of Medicine , provides answers to some of the most frequently asked questions regarding the COVID-19 Delta variant, vaccines and public safety measures.

Drowos is board certified in preventive medicine, family medicine and medical quality. Prior to joining FAU, she served as the center medical director of the Riviera Beach Health Center of the Palm Beach County Health Department. At the health department, Drowos participated in the care of the county’s medically underserved populations addressing various infectious diseases such as HIV/AIDS and tuberculosis. She also served as the director of medical education for the Palm Beach County Health Department’s Preventive Medicine Residency Program from 2009 to 2013.

  1. What is the Delta variant?

As the COVID-19 pandemic has been impacting countries around the world, genetic variants of SARS-CoV-2 have been emerging and circulating. Variants of viruses occur when there is a change or mutation to the virus’ genes. It is not unexpected that the virus causing COVID-19 is changing, as it is the nature of RNA viruses to evolve and change. Mutations in viruses are neither new nor unexpected. Viral mutations and variants in the United States are routinely monitored through sequence-based surveillance, laboratory studies, and epidemiological investigations. The B.1.617.2 (delta) variant of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), has contributed to a surge in cases across the globe, and in the U.S., data from the U.S. Centers for Disease Control and Prevention (CDC) suggest that currently more than 80 percent of cases of COVID-19 are the Delta variant.

  1. How quickly does the Delta variant spread?

Evolving research suggests that the Delta variant is spreading more aggressively than previous virus strains because of a higher viral load carried by infected individuals. Researchers suspect that Delta is about 50 percent more transmissible than the Alpha variant, which means the average patient would infect 50 percent more contacts. Alpha itself is an estimated 50 percent more contagious than earlier versions of the virus. Earlier in the outbreak, under certain conditions, an infected person may have transmitted to two or three people. Now, with the Delta variant, that number could be five to nine, resulting in a greater amount of spread from each infected person.

  1. Why is the Delta variant worse than the previous strains?

Compared to the earlier virus strains causing COVID-19 infection, the Delta variant is the most infectious variant of SARS-CoV-2 to emerge yet. The Delta variant is about 50 percent more transmissible than Alpha, the previously most-infectious form, and almost twice as contagious as other circulating strains. In terms of available research about symptoms based on the experience of other countries, the Delta variant presents slightly differently. Common symptoms include headache, runny nose and a sore throat, more like an upper respiratory tract infection, with fewer symptoms like coughing, shortness of breath, and change in taste or smell. The fast-spreading Delta variant is believed to be contributing to the recent uptick in COVID-19 cases in certain areas, particularly among those who have not been vaccinated, as well as the current surge in hospitalizations related to COVID-19. According to the CDC, during the recent surge of people requiring hospitalization for COVID-19, 97 percent are unvaccinated.

  1. If I am vaccinated, should I be concerned about the Delta variant?

While vaccinated individuals may experience a breakthrough infection with the COVID-19 Delta variant, they are less likely to experience severe symptoms. The death rate from COVID-19 in the U.S. is rising steadily for the first time in months as cases are again increasing in what the CDC has referred to as “a pandemic of the unvaccinated.” The upward trend in national statistics is being driven almost entirely by outbreaks in places with low vaccination rates. While COVID-19 deaths are considered preventable by the vaccine, unvaccinated Americans now account for almost all recent COVID-19 hospitalizations and deaths.

  1. What is a breakthrough infection?

A breakthrough infection occurs when someone who is fully vaccinated contracts the virus. While COVID-19 vaccines are an effective and critical tool to control the pandemic, no vaccines are 100 percent effective at preventing illness in vaccinated people. There will be a small percentage of fully vaccinated people who will still develop illness. This does not mean that the vaccines are not working against the virus. Like with other vaccines, vaccine breakthrough cases will occur, even though the vaccines are working as expected. Asymptomatic infections among vaccinated people will also occur. Current data suggest that COVID-19 vaccines authorized for use in the U.S. offer protection against many SARS-CoV-2 variants currently circulating in the U.S. However, variants will also cause additional vaccine breakthrough cases. As more and more people get vaccinated, the number of breakthrough infections will also rise, since they will naturally make up a larger share of the overall cases.

  1. How severe are the breakthrough cases?

Thus far, the vast majority of COVID breakthrough infections have not led to serious disease. Data suggests that fully vaccinated individuals are likely to suffer milder disease if they develop symptoms at all. The CDC continues to monitor for the rare breakthrough cases that may result in serious infection or death. In other countries, many vaccinated individuals have mistaken their symptoms as those related to allergies, or a cold due to their mild nature.

  1. Why should I wear a mask if I’m vaccinated?

Recent research suggests that the Delta Covid-19 variant produced similar amounts of virus in vaccinated and unvaccinated people if they get infected. While vaccination makes it less likely that you’ll catch Covid-19 in the first place, however if you are infected you can spread the infection as easily as unvaccinated individuals. Higher viral loads suggest there is increased risk of transmission of an already more contagious variant, raising concerns that unlike with other variants, vaccinated people infected with Delta can transmit the virus. When worn properly, a face mask helps block respiratory secretions produced by the wearer from contaminating other persons and surfaces and reduces transmission of the virus.

  1. If I can still get infected with the Delta variant after I’m fully vaccinated why even bother getting vaccinated?

While there is still the possibility of becoming infected with COVID following vaccination, your chances of developing serious illness are significantly reduced. Currently available data show that while the authorized COVID-19 vaccines may be less protective against the Delta variant compared with earlier versions of SARS-CoV-2, they still largely remain effective, and more importantly they are very good at preventing serious disease and death. Presently, the majority of serious illness and hospitalizations are occurring among unvaccinated individuals.

  1. How prevalent is the Delta variant in Palm Beach County and in Florida overall?

According to current estimates from the CDC, 83 percent of U.S. cases of COVID-19 infection are attributed to the Delta variant. As of July 30, Florida was experiencing a surge in cases and had set a record-high for the number of positive cases in one day at 110,724, and a record high number of deaths in one day at 409. The previous seven-day averages for these same numbers were 27,681 and 102 respectively. Florida, which represents about 6.5 percent of the U.S. population, is accounting for about 21 percent of the country’s new cases. Palm Beach County reported 9,939 new cases between July 19 and Aug. 1, suggesting that cases in our county are increasing as well.

  1. How long will the Delta variant last? Will there be another variant after this one?

Projections from the COVID-19 Scenario Modeling Hub, a group of researchers working with the CDC to help track the course of pandemic, released new projections on July 21, predicting trends in the current spike in coronavirus cases. The researchers used statistical models to create four possible scenarios that vary based on percentages of vaccinated people in the U.S., and how quickly the Delta variant spreads. Their current prediction suggests the current wave fueled by the Delta variant is likely to continue throughout the summer and fall, and peak in mid-October. At that point, there will be some immunity and less of a susceptible pool of people for potential infections and the infection rates will start to slow and return to their level before the spike. As far as whether there will be other variants, genetic variants of SARS-CoV-2 have been emerging and circulating around the world throughout the pandemic. It is possible that other variants will emerge in the future. Viral mutations and variants are routinely monitored through sequence-based surveillance, laboratory studies, and epidemiological investigations, with recommendations changing as the situation evolves.

  1. Why are health care workers refusing the vaccine? Shouldn’t they be the first ones to roll up their sleeves?

Some health care workers have refused the vaccine, as they are hesitant to accept the vaccine for the same reasons that many other Americans have not accepted the vaccine. This includes mistrust of this vaccine and its technology, and fear of side effects, much of which is based on myths about the vaccine. Health care workers do have a responsibility to protect vulnerable patients or those who are unable to get the vaccine.

  1. Why does the CDC keep changing their position on masking and other recommendations? It seems as though they are sending mixed messages to the public.

The CDC reversed its masking recommendations for vaccinated adults as concerns over the Delta variant of Covid-19 increased. The updated recommendation urges vaccinated people in certain areas of the country to resume wearing masks indoors in public areas. This recommendation applies to areas with either “high” or “substantial” transmission, which includes most of Florida, as well as 46 percent of U.S. counties experiencing high transmission and 17 percent with substantial transmission. This change relates to the fact that the Delta variant behaves differently than other variants; there are new scientific studies showing it is significantly more infectious, and that it can cause infection as well as be transmitted by those who are vaccinated. The guidance for people who are unvaccinated has not changed and involves wearing a mask until you are fully vaccinated.

  1. What does the Delta variant mean for people who are immunocompromised?

There is a lot of diversity related to the reasons why people who are immunocompromised, as well as how their body may produce a response to the vaccine. Whether someone is immune-compromised because they have an underlying condition that weakens their immune system, or they have an underlying condition requiring immune-suppressing therapy, there are many factors that will impact their risk from the Delta variant. Factors that might affect someone’s response to a vaccine include the medication they’re taking and what it does, how long they’ve been taking it, or their specific disease, and their history of infection. It is important to check in with your physician to understand your particular risk. In general, immunocompromised people are encouraged to get the vaccine, and then layer their protection through masking, hand-washing and social distancing in order to reduce the likelihood of becoming infected.

  1. What does the Delta variant mean for children who are too young to get vaccinated?

Currently in the U.S., the Pfizer-BioNTech is available for anyone over age 12. For children who are not yet eligible to receive the vaccine, they can be protected by the adults around them getting the vaccine, wearing masks and using social distancing strategies. Clinical trials are currently underway to determine the dosing and efficacy of the vaccines in younger populations. National data shows a rise in pediatric cases during the first two weeks of July as cases increased nationally, pediatric cases represented 43,033 of new cases over the same time period.

  1. Are children more at risk from the Delta variant than previous strains of COVID-19?

Studies show that the Delta variant is far more contagious than the original virus strain. While there have been breakthrough cases among those who are fully vaccinated, the Delta variant disproportionately affects people who are not vaccinated. For children under 12 who are not yet eligible to receive the vaccine, as well as many tweens and teens who are eligible but not fully vaccinated to date, children now make up a larger proportion of new cases as more adults are vaccinated. Data on whether the Delta variant causes more serious illness in children will be monitored closely.

  1. Should young adults be concerned about the Delta variant?

Earlier during the pandemic, the majority of the younger population getting infected with COVID-19 experienced minor symptoms. In recent weeks, that trend is changing with the emergence of the more contagious Delta variant that disproportionately affects those who are unvaccinated. At the same time, the 18 through 29 age group has the lowest vaccination rate among adults, and also have the potential for exposure because of their activities. This has resulted in a spike in infections in this unvaccinated young adult population, which can be expected to increase as more cases occur, as well as more serious infections occurring among this age group. Young adults are encouraged to get fully vaccinated, and follow CDC recommended precautions for reducing their risk of infection.

  1. How effective are the current vaccines against the Delta variant?

Data show that while the authorized COVID-19 vaccines may be less protective against the Delta variant in preventing infection and minor illness compared with earlier versions of SARS-CoV-2, they still largely remain effective, and are very good at preventing serious disease and death. These are the most critical outcomes to prevent and show that there is significant benefit from receiving the vaccine. It can be expected that as vaccination rates increase, more and more of the people who get COVID-19 will have been immunized, even as fewer total people get the disease. Even with diminished effectiveness against the Delta variant, vaccines remain our most important tool to prevent serious illness and death, and to control the pandemic.

  1. Should I consider getting a booster shot if it’s been more than six months since I was fully vaccinated?

Presently, the CDC does not recommend booster doses for individuals who are fully vaccinated against COVID-19. A booster dose is defined as an additional vaccine dose given after the primary (one or two-dose) series, that are needed to increase immunity after the initial immune response wanes. Any updates to the current immunization schedule recommendations would involve coordination with the U.S. Food and Drug Administration (FDA) to update the existing Emergency Use Authorization (EUA) and would target specific populations. Data to inform these decisions will consider an individual’s risk of COVID-19 exposure, risk of complications from infection, risks of waning immunity, as well as the risks of variant strains. These recommendations will be adjusted as additional data is available and analyzed.

  1. It concerns me that all of the vaccines are only authorized for emergency use by the FDA. Why haven’t they fully approved the vaccines?

Emergency use authorization (EUA) was developed to be a relatively flexible and faster process that allows adaptation and response to a variety of emergencies, such as a global pandemic. In the case of COVID-19 vaccines, the first received an EUA on Dec. 11, 2020 after the company presented data that the benefit outweighed the risks of vaccination. The lengthier review to offer full licensing to vaccines takes additional months of data collection, as well as significantly more time by the FDA in reviewing every available piece of data. The FDA will take the time to complete a high-quality review that U.S. citizens have come to expect. The FDA has said the Prescription Drug User Fee Act goal date where they will have completed this extensive process is January 2022 at the latest.

  1. Should I wait for the FDA to grant full approval of the vaccines before I get vaccinated?

While it true that there is a higher bar to clear for full FDA approval, EUA requirements for a vaccine assure safety and efficacy. The largest difference is the speed needed to respond to an emergency. Both full approval and an EUA require a certain number of people to be treated with the vaccine or a placebo in a clinical trial and require evidence that the vaccine reduces the frequency and severity of infection, as well as proof that it is manufactured with consistent purity and potency. The currently available COVID-19 vaccines are safe and efficacious and will be under consideration for full FDA approval.   

  1. Is it too late to get vaccinated? Will it make a difference?

The COVID-19 vaccine, like other vaccines, can take 10 to 14 days to be fully effective. Getting the vaccine as soon as possible provides the best chance of protection from serious illness and hospitalization. If you were to get exposed to COVID-19 too soon after getting vaccinated you may still get ill, however getting vaccinated after having COVID-19 offers additional benefits. Even after having COVID-19 previously, your body may not have generated an adequate antibody response, or immunity may have waned over time, or you may not be protected against variants, which is why it is still important to get vaccinated now.

  1. Besides getting vaccinated, what else can I do to protect myself and others?

In addition to getting the vaccine, wearing a mask can protect yourself and others, particularly when indoors and unable to adhere to social distancing. Avoiding crowds indoors, particularly when you are unable to remain 6 feet apart from others, and spaces with poor ventilation is also important. Washing your hands frequently, covering coughs and sneezing, and frequently disinfecting surfaces are other helpful strategies. You can also monitor your own health and stay away from others and get tested if you are showing signs of illness.

  1. How are we going to manage the variant once children are back to school? Most of them are not vaccinated.

The experience of the previous school year has shown that opening schools for in-person learning generally does not significantly increase community transmission when masking and other safety measures are in place. Since the COVID-19 Delta variant has emerged that may increase the risk of transmission and result in worsening illness, the CDC and the American Academy of Pediatrics (AAP) have issued updated guidance that involves layering protection to limit COVID-19 transmission. Both agencies agree that in-person learning is important and recommend vaccination as an important strategy for all who are eligible. The CDC recommends universal indoor masking for all teachers, staff, students, and visitors to K-12 schools, regardless of vaccination status. In addition to vaccinations, the AAP recommends a layered approach including a recommendation that everyone older than age 2 wear masks, regardless of vaccination status. The AAP also supports the CDC’s recommendations for building ventilation, testing, quarantining, cleaning and disinfection in school buildings.

  1. Are current COVID-19 tests able to distinguish if a positive test is due to the Delta variant?

Current commercially available COVID-19 tests can’t always detect the Delta variant. The Delta variant carries distinctive biological markers that some of these tests are not able to sense. Testing for variants requires genomic sequencing, which is expensive and not able to be performed by many laboratories. State health departments may run tests to help determine prevalence of a particular variant in that state, but it is unlikely individual patients would learn which variant they are infected with.

  1. Is Florida tracking Delta variant cases?

Florida is currently tracking the total number of COVID-19 cases, which includes the Delta variant and other SARS-CoV-2 variants in combination.

  1. If I have been fully vaccinated and I’m exposed to someone who has been infected with the Delta variant, do I still need to get tested and do I have to quarantine for 14 days?

Updated guidance from the CDC for vaccinated individuals with a known exposure to any variant of COVID-19 suggests testing three to five days following exposure, whether or not you have symptoms. You should also wear a mask indoors in public for 14 days following exposure or until your test result is negative. You should isolate for 10 days if your test result is positive.

  1. What populations are most at risk from the Delta variant?

Unvaccinated people are most at risk from infection with the COVID-19 Delta variant. They are more likely to suffer serious illness and require hospitalization, when compared to symptoms experienced by individuals who are vaccinated. Even younger, healthier adults without comorbidities are experiencing significant illness as a result of COVID-19 infection resulting from the Delta variant when they are unvaccinated.

  1. If I get infected with the Delta variant, what are the treatment options?

There is currently no cure for COVID-19 and the goal of treatment is to relieve symptoms in mild to moderate cases. Treatment is the same regardless of the infectious variant. Patients with mild to moderate symptoms are usually advised to remain home and self-isolate for at least 10 days to avoid spreading the virus. Treatments for mild to moderate COVID-19 symptoms include rest, increasing fluids, and over-the-counter pain relievers and cough suppressants. In some cases, your physician may suggest Casirivimab/imdevimab (Regen-COV), a monoclonal antibody combination that received EUA from the FDA to treat mild-to-moderate COVID-19 in adult and pediatric patients who are at high risk for progressing to severe COVID-19 and/or hospitalization. More severe COVID-19 cases may require hospitalization and treatments may include corticosteroids, immunotherapy, antiviral therapy with remdesivir, antithrombotic therapy, oxygen and ventilation when needed. Monoclonal antibodies are not indicated for use in severe cases. Hydroxychloroquine is not recommended to treat COVID-19. Current guidelines neither recommend nor advise against the use of vitamin C, vitamin D, or zinc for COVID-19. Zinc should not be taken in doses above the recommended daily allowance (RDA) due to the risk of toxicity.

  1. If I get infected with the Delta variant should I go to the emergency room?

If you think you were exposed to COVID-19, or have mild symptoms, you can schedule a test at several locations throughout the community. If you are experiencing mild symptoms, it is okay to stay at home and self-quarantine. Increasing rest, drinking fluids, and using over-the-counter pain relievers or cough suppressants can help alleviate your symptoms. It is important to monitor your health for any severe or worsening symptoms. Symptoms that indicate more severe illness and should prompt seeking care include shortness of breath while at rest, dry cough, fever, breathing becoming more difficult, a significant or worrisome cough that is increasing, confusion or sudden change in mental status, chest pain, low oxygen levels, extreme sleepiness or inability to wake, and blue face or lips.

  1. How many variants of COVID-19 are there?

SARS-CoV-2 like all viruses, is constantly mutating. At present there are 11 different named variants of the virus so far, named for the Greek alphabet (alpha-iota). The places where these genetic mutations are first identified are not necessarily where they first evolved and relate to how much genotyping countries are doing. The vast majority of mutations do not provide the virus any benefit in transmission, and some can actually limit spread of the virus. The mutations that are advantageous to the virus are rarer, however if there’s a mutation that allows a variant to be more transmissible, it will become dominant and other strains will become less present.

  1. Where did the Delta variant come from? How did it get to Florida?

The Delta variant was first identified in India in December 2020 causing a significant outbreak. Since that time, it has rapidly spread and is now reported in 104 countries. As of early July, Delta has become the dominant form of the coronavirus in the U.S., U.K., Germany, and other countries. Variants can spread to neighboring countries, through commerce or travel, and due to their benefit in virus transmission can become the dominant cause of infections.

  1. Are we headed for another lockdown?

While the lockdowns of 2020 provided time for scientists to learn more about COVID-19 and prevented hospital systems from becoming overwhelmed, they resulted in economic challenges, impacts on mental health, education and other public health concerns when access to medical care was limited. We now have vaccination as an available tool that is working well against currently circulating variants. Coupling vaccination with other public health measures such as masking, hand-washing and social-distancing will help control the pandemic.


The answers to these questions are not meant as medical advice. They are intended to provide information that during a pandemic can change as we learn more about the virus and the vaccines that have been and are being developed. The information provided is the best available as of Aug. 3, 2021. For questions about specific circumstances, consult with a physician.