I volunteered for a COVID-19 vaccine trial

I volunteered to participate in a phase 3 COVID-19 vaccine trial, here’s why:

COVID-19 is not going anywhere. As everyone by now knows, you can protect yourself by staying 6 ft away from others and washing your hands frequently. If infected people (with or without symptoms) wear masks, the spread of the virus will slow. These 3 things together are currently all we have to stop more infections from happening.

A vaccine is what is needed to halt COVID-19

Once enough people are inoculated with an effective vaccine, the virus will die out as it will not find many new hosts to infect. The idea of all people wearing masks in public works via a similar mechanism – a physical (much less effective) vaccine of sorts.

We need volunteers to develop an effective vaccine as quickly as possible. We all know vaccines work: smallpox no longer exists in the wild, it is exceedingly rare to see people with lingering effects from polio, families do not lose 3 or more children in 1 year due to diphtheria. I believe in the efficacy and safety of vaccines and I want to actively participate in the solution to combat COVID-19.

While there are currently 140 vaccines being explored it is important to remember that the process to develop a safe and effective new vaccine is typically a lengthy one lasting 10-15 years or longer. Currently, there are 23 vaccine candidates in human clinical trials around the World (US, China, UK, Germany, S Korea, Australia, India, Canada, Japan, and Russia).

The Vaccine Development Process

The process for developing a vaccine begins with the Exploratory stage where potential candidates are worked on that might work. Then the Preclinical stage where safety and efficacy are tested on animals.

This stage is followed by the Clinical Research stage with 3 phases of clinical trials:
1) Phase 1 – Tested on 20 to 100 healthy adults to see how it works.
2) Phase 2 – Tested on up to several hundred people to evaluate the vaccine’s safety, immune response, proper dose, dose schedule, and method of delivery.
3) Phase 3 – The vaccine is tested on 300 to 30,000 people or more to determine how safe the vaccine is among a large group of people.

If a candidate passes Phase 3 clinical trials, it is submitted for approval and licensing by the FDA. It continues to be studied in Post-licensure monitoring after implementation in the public.

COVID-19 Vaccine Candidates

Right now there are several types of vaccines being tested in human clinical trials.

  1. RNA/DNA – Vaccines use genetic material copied from the virus to mimic the natural infection of the coronavirus and cause a person’s immune system to mount a response.
  2. Protein subunit – Vaccines contain proteins taken from the coronavirus that are directly injected into the body to produce an immune response. Current vaccines that work this way include: human papillomavirus infection (HPV), hepatitis B, and shingles vaccines.
  3. Viral vector – Vaccines contain a different virus that is dead or weakened, but includes genetic material from COVID-19. The immune system responds and builds a defense against the genetic material, which then prevents an actual infection.
  4. Weak or inactivated – These types are commonly used for the flu. They contain a weak or inactivated form of COVID-19 to stimulate a person’s immune system to build antibodies. These antibodies can later recognize the virus if an infection happens and trigger a quick, targeted response to fight it off.
  5. Virus-like particle vaccine – These vaccines mimic the structure of the virus, but they don’t include any genetic material. Similar vaccines are hepatitis B and human papillomavirus (HPV) vaccines.

Current Phase 3 Vaccine Candidates

  1. An RNA vaccine made by Moderna and the National Institute of Allergy and Infectious Diseases in the US. Their results from phase 1 that showed an immune response in all participants! Phase 3 begins in July.
  2. A viral vector vaccine made by the University of Oxford/ AstraZeneca/ Serum Institute of India in the UK.
  3. An inactivated vaccine made by Sinovac in China. They are approved for phase 3 but have not begun enrollment.

I am excited about the prospect of both participating in this historical period of vaccine development and selfishly, my own potential immunity from COVID-19.

The COVID-19 prevention clinical studies volunteer registry questionnaire was simple and quick to fill out. If you also would consider volunteering, I encourage you to join me!

July COVID-19 Update Summary for Florida

COVID Update

COVID-19 is a viral infection touching many extended families throughout the World. As each of us learns of the experiences of those we know and trust, we gain personal insight into it.


People who are sick with COVID-19 often feel profound fatigue, have a dry cough that can make it difficult to speak, and might have uncomfortable high fevers.

Florida Cases

The news has been reporting on our recent surge of new cases here in Florida. Florida has had a total of 4,409 deaths from 291,629 total infections. The first half of July, alone, produced 17.8% of all the Florida cases since the beginning of the pandemic.


With the increase in cases, we need to be mindful of hospital capacity to handle this increased load. As of today, hospital bed remaining capacity in Florida is 21% and ICU beds 17%. With 8,345 people with COVID currently hospitalized in Florida, we continue to have remaining capacity to care for patients.

Rate of Spread

The rate of spread of infection is measured by R0. Our current R0 is 1.09, down from a high of 1.34 in early June. This means that every infected person is spreading the infection to an aditional person out of every 11 people they interact with. The spread will slow down when the R0 drops below 1.

To drop our R0, we need to find ways to live normal lives where we can maintain spacing (6ft or more) between people and measures to decrease transmission potential (frequent hand washing and protective masks).


I would like to remind everyone that many patients do not require hospitalization and recover safely with over the counter measures at home. At this time, we have no medications to cure COVID-19. There are some that help people feel better, but none have been shown to help you get better faster.

  • But what about Remdesivir? For those with severe illness in the ICU, it helps – but not for those who are not hospitalized.
  • What about hydroxychloroquine? The jury is still out. It is only being used for clinical trials right now.
  • What about budesonide? Maybe for those with asthma, they will feel better. The jury is still out on this otherwise as well given how corticosteroids have a potential for prolonging viral replication (worsening COVID-19)

Treatment remains symptomatic care which means simply addressing symptoms. If there is nausea, we treat nausea. If there is cough, we treat cough. For fatigue, rest.

We also have found that breathing exercises help as does spending time laying on your stomach.

Testing and When to Return to Work

Not everyone needs to be tested. An astounding 2,688,366 COVID-19 tests have been performed so far here in Florida! It is my opinion that asymptomatic people in general, do not need to be tested.

If you have had close contact (less than 6 feet for several minutes) with someone who has COVID, you can quarantine for 14 days after your last contact (as per CDC).

The CDC also has return to work guidelines. You can return to work if at least 3 days (72 hours) have passed since recovery (defined as resolution of fever without the use of fever-reducing medications and improvement in respiratory symptoms) and at least 10 days have passed since symptoms first appeared.

To summarize:

  • Cases have been rising
  • But we continue to have sufficient capacity as a whole across Florida
  • The spread is slowing as R0 has improved from 1.34 to 1.09
  • But there is more to go – the virus is still increasing its spread in Florida
  • We need to continue to be creative as we learn how to live with this virus, which is not going away anytime soon.



What does a positive COVID-19 test result mean?

What does a positive COVID-19 test result mean?

I would like to provide context on what a positive (or negative) COVID-19 test result means.

In short, for low prevalence diseases, there are high false positive rates.

Without getting too much into the weeds, I came across this great interactive website demonstrating the biostatistics behind COVID19 testing.

The fact is, we do not know the prevalence (how many people have COVID-19 in the population at any moment). How many people have the virus changes how we interpret positive and negative test results.

The higher the prevalence, the more people who have COVID-19 at any one time, the more likely a positive test result is a true positive and not a false positive. This is called Positive Predictive Value (PPV).

Using published sensitivity and specificity from a real COVID-19 Rapid Antigen test, I calculated the PPV for 4 scenarios with different prevalence:

  • Testing in Florida has consisted of those with symptoms, exposure to people with COVID-19, retesting to assure recovery, and those with concerns for COVID-19. This increases the likelihood of a positive result. The positive rate of this population is 8%. I used this as a high prevalence rate.
  • The estimated COVID-19 prevalence in Miami is 6% – the highest in the state. This is a more realistic high prevalence rate.
  • I also ran 3% and 1% prevalence rate scenarios as I suspect those are closer to real numbers for the state.

What I found:

  • If you have a negative COVID-19 test result in any of these scenarios, you can be more than 99.99% sure you do not have COVID-19!
  • If you live in Miami and have a positive COVID-19 test result, you only have a 50.3% chance of truly having COVID-19! There is a 49% False Positive rate for that estimated prevalence!
  • For the state of Florida, I think the overall prevalence is 1-3%. Anyone in Florida with a positive COVID-19 test, the overall likelihood you really are infected by COVID-19 is somewhere between 13-33%!

So Many COVID-19 Models and Predictions

There are many models being discussed right now with attempts to predict what will happen with the COVID-19 pandemic.
I urge you to be cautious with COVID-19 projections.
Every model begins with assumptions. Any error or unexpected variation in these assumptions builds on the other assumptions (and their errors/variations) and results in potentially inaccurate conclusions for many of these models.
  1. Take (common sense) appropriate actions to minimize risk
    1. Social distancing
    2. Hand washing
    3. No face touching
    4. Disinfecting high-touch surfaces)
  2. Feel free to listen to the possible model outcomes, but avoid thinking of them as a certainty.
What ends up happening will depend entirely on how we, as a society, react to this disease.
  • Take it seriously
  • Do the actions to not put yourself or your family at risk

Answers to Frequent COVID-19 Questions

A Letter I Sent To My Patients This Week


As I write this, we have had 1,171 COVID-19 positive cases in Florida so far. As a global community, we need to work together as a unified team to stop this pandemic as fast as possible. Building on my last email, I want to provide some answers to some common questions I have been asked by my patients:

How contagious is this virus?

Remember: Without contact with someone who has COVID-19, you cannot get it.

This virus is quite contagious and continues to spread. While quite contagious, it is spread by droplets and is not aerosolized. This means you will not likely get it by simply standing next to someone with it, walking past someone, or even touching them. You cannot become infected with this virus through your skin.

Were that infected person standing or walking by you cough or sneeze in the air and you breathe those droplets in, you can get infected. Should you shake the hand they coughed into, or doorknob they touched and then itch your eye, nose, or mouth, you can get infected.

The contagiousness of a disease is often expressed scientifically in a notation called R0. The R0 for COVID-19 is estimated around 2-3 right now (there are many variations on this estimate). This means that right now 1 person infects around 2-3 other people.

For comparison’s sake, here are some other diseases and their R0:

  • COVID-19: 2-3 (estimated)
  • HIV: 3.6-3.7
  • Seasonal Flu: 1.3
  • Measles: 11-18

This demonstrates the need for social distancing, hand washing, and avoidance of touching your face. Again, without contact with someone who has COVID-19, you cannot get it.

What are the symptoms of COVID-19?

COVID-19 symptoms overlap with other common seasonal conditions. These include Influenza (currently still prevalent), seasonal allergies (pollen counts are HIGH in Central Florida), and other viral colds.

As a member of a Direct Primary Care office, you have the luxury of reaching out any time you feel concerned. Please do not hesitate to call, text, or e-mail me with any questions about potential symptoms. I am happy to discuss these with you.

Symptoms for this virus begin 2-14 days after exposure. The most common symptoms are:

  • Fever (over 100.5 F) – Most patients have fever.
  • Cough
  • Shortness of breath

Should more severe symptoms occur, call 911 and explain concern for potential COVID-19. These severe symptoms include:

  • Trouble breathing
  • Persistent pain or pressure in the chest
  • New confusion or inability to arouse
  • Bluish lips or face

How do I avoid getting it?

AVOIDANCE! Remember: Without contact with someone who has COVID-19, you cannot get it.

All strategies revolve around avoidance of potential exposure to the virus.

  • Practice good hygiene:
    • Wash your hands (for at least 20 sec) frequently
    • Avoid touching your face
    • Cough or sneeze into a tissue or the inside of your elbow
    • Disinfect frequently used items and “high touch” surfaces as much as possible (Your phone is very dirty!)
  • Work or study from home
  • Avoid social gatherings, especially if there are 10 or more people
  • Avoid discretionary travel, shopping, and social visits

Avoid spreading this virus to those at high risk:

  • Do not visit nursing homes, retirement homes, or long-term care facilities. One nursing home facility in Washington suffered 26 deaths when COVID-19 was transmitted there.

People of all ages can become infected with COVID-19. While those who are younger are less likely to experience severe episodes, they can easily spread the disease to others who are higher risk. Working together to contain the spread of this virus is important for all of us.

Am I a high risk person?

If you are an older person and/or have a chronic health condition, stay home and away from other people.

Those who are higher risk should they become infected with COVID-19 are:

  • People aged 65 years and older
  • People of any age with excess weight with a body mass index (BMI) over 40
  • People with chronic lung disease or moderate to severe asthma
  • People who have heart disease with complications
  • People who are immunocompromised including cancer treatment
  • People who live in a nursing homes or long-term care facilities
  • People with underlying medical conditions like diabetes, kidney disease, or liver disease

If I get infected, what is the treatment?

It is important to remember that most people can be safely treated at home (81% of all COVID-19 positive cases according to one study). Current hospitalization rate in Florida is less than 20%.

There is no vaccine nor specific antiviral medication for COVID-19. Management mostly consists of treating symptoms and avoiding further exposure to others.

Symptomatic treatment includes assuring sufficient fluid hydration, cough suppression with dextromethorphan, zinc supplementation, and acetaminophen for muscle aches/joint pains.

If you are infected, avoid spreading COVID-19 to others.

  • Wear a mask – face masks will not protect you from COVID-19, but will help prevent the spread of the disease to others
  • If you feel sick, stay home. Do not go to work.
  • If your children are sick, keep them home.
  • If someone in your household tests positive, keep the entire household at home.

Have you heard about the caution regarding using ibuprofen?

This idea came from a French report based on some anecdotes. The evidence against its use is very weak. At this time, I think there is not enough evidence to say ibuprofen will result in worse disease process. If you have specific concerns, please reach out.

What about these other treatment modalities like hydroxy-chloroquine?

There are several medications currently being studied for effectiveness. There are some moving stories being reported in the news as well. These are all promising and provide glimmers of hope. I urge caution on placing too much weight on these treatment modalities until they are tested further.

I am aware of 3 potential vaccines in development, 4 different antivirals, and 4 medications from the biologics class with potential to treat COVID-19 and improve outcomes. As you are able, avoid the expectation for a rapid cure and instead concentrate your efforts on prevention.

How do I get tested?

First, think: Should you be tested?

The testing criteria are pretty strict. Not everyone needs or should be tested.

Here are the current CDC recommendations for testing (and what I and other Central Florida doctors are following):

  • If you have symptoms of acute lower respiratory illness (e.g., fever, cough, and shortness of breath) AND meet one or more of the following criteria:
  • Have had a close contact with a laboratory-confirmed COVID-19 case.
  • Are hospitalized with acute lower respiratory illness of unknown origin.
  • Have a history of travel to or from an affected geographic area with widespread community transmission.
  • Have traveled internationally or been on a cruise.
  • Are over 65 with chronic health conditions.
  • Are immunocompromised.

Should you meet these criteria, call the office, and I will order a test for you.

Remember, a positive or negative test does not affect your treatment much unless you develop severe symptoms.

If you feel sick, whether it is COVID-19, the flu, or any other cold, you should stay home, avoid other people, wash your hands frequently, cover your coughs, and disinfect surfaces. Treatment for most COVID-19 cases (and other colds) are managing symptoms and avoiding getting others sick.

As always, if you have questions, concerns, thoughts, suggestions, or any other comment, please do not hesitate to reach out to me!

Stay healthy,

Dr. Matt