Frequently Asked Questions

The virus that causes COVID-19 and the disease COVID-19 have had multiple names. The virus in the early months was called “coronavirus” or “Wuhan Virus” since its in the large, diverse family of coronaviruses and Wuhan was the city in China where it was first discovered. To decrease stigma against China and Chinese people and to be more clear about the virus and the disease, in February, 2019 the World Health Organization came up with new names. The virus is called Severe Acute Respiratory Syndrome Corona Virus-2. In shorter form SARS CoV-2. The virus causes the disease COVID-19 which got its name from CO for corona, VI for virus, D for disease and 19 for 2019, the year the outbreak was first identified (31 December 2019).

The first cases of the COVID-19 disease were reported in the city of Wuhan, China in December of 2019. At the time we thought the virus causing the COVID-19 disease, the SARS CoV-2 virus, was being carried by animals in a large outdoor market. Now the most likely source of the virus was in bats. Many viruses besides SARS CoV-2 live in other animals – bats, chickens, pigs, birds – then cross-over to infect humans. Any situation where large numbers of people live or work closely with other animals, creates a greater risk of animal infections entering the human population.

The most common way to spread is breathing in water droplets when someone infected with SARS CoV-2 coughs or sneezes near another. You can also spread the infection if water droplets leave your mouth with any activity where you force air through your mouth and nose such as talking, shouting, blowing through a musical instrument. Most water droplets fall to the ground within six feet when they leave your mouth. This is why we advise social distancing of six feet. If you wear a cloth mask, it catches the water droplets to protect other people. Its also possible the virus can spread through the air without the need for water droplets. This could partially explain why infections indoors with poor ventilation are far more common than exposures outdoor or in rooms with good airflow. People can also spread it by touching something that has SARS CoV-2 water droplets e.g a door handle then rubbing it your eye, or touching your mouth. This is far less common than breathing water droplets.

When a high percentage of a community, city, region, country have either been vaccinated or have natural protection because they survived COVID-19, eventually the amount of virus circulating in that “herd” of people becomes very low. As a result, the few unvaccinated people remaining in the “herd” are very unlikely to bump into another unvaccinated person who is also infected. So the decision to get a vaccination by the majority of the “herd” protects or provides “immunity” to the few who decide vaccination is not for them. This “herd immunity” is an example of individuals making decisions that benefit themselves and benefit the community.

Most of our viral vaccines are made by one of three approaches

Dead virus or bacteria – Scientist grow the virus in larger amounts. Kill it, then purify parts of virus to be injected as a vaccine. This is how all polio vaccine is made for Americans. Also most common for the annual flu vaccine.

Alive, but weak virus– Scientists grow virus in large amounts, then weaken it so it can’t make a person sick. Then inject the alive, weaker virus as a vaccine. Some flu vaccine is given this way. This is how oral polio vaccine is made.

Genetic material – Scientists use the RNA or DNA of a virus alone or placed into another virus. Inject this genetic material as a vaccine so the person’s cells create proteins that activate the defense mechanisms of the immune system. Some influenza vaccines are made this way.

The major difference with the COVID-19 vaccine it’s the first to use messenger RNA as the genetic material rather than DNA or another virus.

Once the companies learned from the vaccines were about 90% effective preventing COVID-19 and nearly 100% preventing death from COVID-19 they applied to the FDA to go to the front of the line to have the vaccines reviewed. After a group of scientists not involved in running the research trials reviewed all the data, they decided because the need for a vaccine was so great, and the large amount of data showed the vaccines were tolerated by 100,000s of people to a degree we expect for all vaccines and that they were extraordinarily effective preventing illness and death, the benefits of giving the vaccine outweighed the risks. The FDA then gave an Experimental Use Authority (EUA) to the companies to administer the vaccine. The approval requires the companies will study the effects of the vaccines for years and that they will proceed with completing the process to get a formal FDA drug approval expected to be given by the end of 2021.

Once a person is infected, we know people of older age are at highest risk for having the most severe illness and greatest chance of dying. The risk increases steadily each decade of age over 50 years old. For example compared to someone aged 20, a 85 year old person is 15 times more likely to be hospitalized and 610 times more likely to die if infected. This is a combination a more severe inflammatory response in older people combined with older people having more chronic disease than young people. We know chronic diseases like diabetes, heart failure, emphysema and bronchitis of the lungs, HIV/AIDS all increase the chance of severe illness and death at any age. When these diseases occur in older people the combination increases the odds for bad outcomes.

Each of the three vaccines use genetic material to direct cells in our body to make the SARS-CoV-2 spike protein. Once our cells make the spike protein, its released into the blood where our immune system recognizes it as something other than part of our body. So it makes an inflammatory reaction to get rid of it. The immune system remembers the spike protein so it if your body is exposed to the actual, fully functioning virus weeks, months later, it will know to clear the virus, preventing an infection or preventing a serious infection.

A small number of infected people will get infected. The vaccines are about 90% effective, not 100% effective. For those vaccinated people who get infected, we know they infect very close to no other people. From studies of the immune system, we think this is because a combination of protective antibodies and immune cells prevent the virus from reproducing so it can’t make enough virus in a respiratory water droplet to infect another person. In this way the immune system holds the virus inside the infected person, until it passes away over the course of 5-10 days when the person is no longer at risk of infecting another.

Because COVID-19 is a brand new disease, no person on earth had natural immune system protections. This was main reason it spread so quickly and made so many people sick. The only defense was masks and restrictions of freedom to mover in public. Because closing down society was so devastating the United States, Chinese, Russian and other governments provided hundreds of billions of dollars to medication companies to focus all their attention on making COVID-19 vaccines. This never happened before. This decision took years off the development process.

Once the companies developed vaccines faster than any other vaccines, with part of the billions of dollars in support from the government they ran research trials in 100,000s of people to test if people were safe getting the vaccine, and how effective the vaccines were to protect people from getting COVID-19 and how well they protected people from going into the hospital or from dying. The COVID-19 vaccines were tested in far more people than any other vaccine in the history of science. They compared people who got an injection with no vaccine to those who got the vaccine. People who got the vaccine were about 90% more protected from being infected than people who got a shot with no vaccine. The vaccine provided nearly 100% protection from dying of COVID-19. These are the most effective vaccines we have ever made.

It’s when a person or group of people who are unvaccinated, infected and unmasked mix with lots of other people and spread the infection to lots of people. The most common super spreader events are birthday parties or weddings where people know each other, are eating and drinking, so unmasked, and get very close to each other with dancing, laughing and close conversations. Alcohol in particular increases the chance of spreading since as people drink more, they stand closer, laugher harder, talk louder creating more water droplets for others to breath in while they aren’t wearing masks. The most common super spreaders are infected but don’t feel sick which is why they go to the event.

Reviewing immune function from the first 10,000s of people given the vaccines, so far the protection shows no sign of getting smaller. From these studies we see strong responses by antibodies that can clear the virus. Also we see very strong responses by white blood cells called T lymphocytes that we know are essential to protecting us from viral infection. These vaccines are being studied with more intensity than any other vaccine or medication in the history of science. With each month we are gathering more information to teach us how long the vaccines will last.

The vaccine protects in several ways.

1. Its about 90% effective preventing a person from becoming infected.

2. If a vaccinated person is infected it dramatically reduces the severity of the infection, providing nearly 100% protection from dying of COVID-19 and greatly reducing the risk of needing to be hospitalized.

3. If a vaccinated person is infected, it provides nearly 100% protection from spreading it to another person, a great benefit to the community. This is why vaccinated people don’t have to wear masks in most settings.

Each of the four variants of concern had a mistake or a mutation in the genetic material that made more contagious than the other variants that came before it. The delta variant is about 40-50% more contagious than other variants. As an example for other variants, if it took ten minutes of high risk exposure to get infected, with the delta variant it would only need six minutes of exposure.

Sometimes a person will tell you they have COVID, reminding you had a high risk exposure with them a few days ago. Sometimes an official from the health department will contact you because someone who tested positive gave them the names of everyone they were close to during a time when they could spread the disease. If you are vaccinated, being exposed to someone with COVID has far less risk associated with it.

Most people with COVID-19 experience a mild to moderate illness like a cold that lasts 3-6 days. Some describe feeling tired for weeks. For people admitted to the hospital we see a much higher than expected risk of blood clots. For people with severe COVID-19 requiring weeks in the hospital, those that recover commonly report feeling “foggy” in the head with slow thinking, very little energy, very little desire to do other things.

The best protection for you friends is for them to be vaccinated so that you are less likely to get them sick if you get infected. If you and friends are not vaccinated, then social distance, stay indoors away from other friends who aren’t vaccinated or if you don’t know their vaccination status. If you need to be around friends wear a N95 mask.

From our study of the immune system we learned people who survive a COVID-19 infection have some protection called natural immunity. The vaccines are so good, we learned a vaccination adds even more protection to natural immunity without evidence of causing greater harm.

A vaccine is the single most effective protection you can have. Once you have the vaccine, the next most effective step is to wear your mask indoors when you are around unvaccinated friends or near friends who you don’t know are vaccinated.

1. To prevent dying from COVID-19

1. To prevent getting COVID-19

2. To have more personal freedom to go places, be with loved ones unmasked.

1. Vaccines are too new, people want to wait and see how things go for others.

2. Don’t trust the science, testing or review process for creation of the vaccines was done properly.

3. Personal reasons including politics, religion, trust of medication or health care, trust in people or involvement by those in world with systemic racism.

By providing protection of about 90% from prospect of getting COVID-19, these are the most effective vaccines we have made. At 90% effective that means if 100 vaccinated people have a high risk exposure, 90 will not get infected and roughly 10 will. Importantly, for the few vaccinated people who are effective almost none will die of COVID-19 and the vaccine will also decrease how sick someone will get.

The Moderna and Pfizer vaccines use mRNA, the same genetic material of the virus, to code for the spike protein.

The J&J/Janssen vaccine uses the genetic material from the adenovirus, containing information to code for the spike protein.

By preventing infections effectively, the vaccines reduce the amount of virus living in our society. With less virus out there, the chance of having more mutations leading to variants of concern is far less.

If you have been vaccinated, you only need to quarantine if you test positive for infection. If you are unvaccinated, if the exposure was high enough risk the health department may advice you to stay away from all others for ten days.

If you are vaccinated, getting tested is needed only if you are feeling sick, or if your work or travel plans require it.

If you are unvaccinated, an exposure to someone infected may trigger a need to get tested.

A vaccine is the single most effective protection you can have. Once you have the vaccine, the next most effective step is to wear your mask indoors when you are around unvaccinated people or near people who you don’t know are vaccinated

Social distance, stay indoors away from other people who aren’t vaccinated or if you don’t know their vaccination status. If you need to be around others wear a N95 mask.

Once you have the vaccine, the next most effective step is to wear your mask indoors when you are around unvaccinated family or near family who you don’t know are vaccinated.

Right now we have four variants of concern, with the delta variant now the most common variant in the Bay Area and spreading across the United States.

Variants arise from the mistakes the virus makes copying its genetic material when it reproduces.

All of the symptoms are caused by inflammation. Each person has their own unique immune system. It's not yet possible to predict how the immune system of one person will respond to SARS-CoV2. About 4 out of 10 people who get infected, feel nothing. If they did not have a positive SARS CoV-2 test they would not know they were infected. This is because for reasons we don’t yet understand, their immune system causes very little inflammation when they get infected. About 4 out of 10 people with COVID-19 feel like they have a bad cold, just like any bad cold they had before. They stay in bed because the inflammation makes them feel fatigue, muscle aches, sore throat, a bit of shortness of breath if they walk up steps. About 2 out of 10 people with COVID-19 have so much inflammation, especially in their lungs, they go to the hospital to get extra oxygen. About 5 out of 100 people have so much lung inflammation they need to be in the Intensive Care Unit of the hospital, sometimes for 3-6 weeks. Of people who are sick enough to be in the ICU in San Francisco, of these about 5-15 out of 100 will die. So far, more than 522,000 Americans died of COVID-19.

Reports of death after COVID-19 vaccination are rare. More than 334 million doses of COVID-19 vaccines were administered in the United States from December 14, 2020, through July 12, 2021. During this time, CDC received 6,079 reports of death (0.0018%) among people who received a COVID-19 vaccine within weeks before their death. Reviewing autopsies, clinical records and discussions with health providers of those who died, its not clear the vaccines caused these deaths. To better understand the size of that risk, recognize that each year in the United States about 150,000 -250,000 people die from mistakes made by hospitals, pharmacies and clinics. There has also been some discussion about Severe Inflammation (Anaphylaxis) caused by any of the COVID-19 vaccines. This is rare. Anaphylaxis after COVID-19 vaccination occurred in approximately 2 to 5 people per million vaccinated in the United States. To compare risk, about 3-50 people per 100,000 have anaphylaxis to a medication they buy at a store or take by prescription. This a 10-25 times greater risk than for a COVID-19 vaccination.

Severe blood clots are very rare side effects. As of July 12, 2021, more than 12.8 million doses of the J&J/Janssen COVID-19 Vaccine have been given in the United States. CDC and FDA identified 38 confirmed reports of people who got the J&J/Janssen COVID-19 Vaccine and later developed severe clots. About 2-5 people per 1 million vaccinated. Women younger than 50 years old were the most common with severe clots. Inflammation damage to peripheral nerves causing weakness ( Guillain-Barré Syndrome) is another extremely rare effect. After 12.8 million J&J/Janssen COVID-19 Vaccine doses administered, there have been around 100 preliminary reports of nerve injury. About 9 per 1 million vaccinated. These cases have largely been reported about 2 weeks after vaccination and mostly in men, many 50 years and older.

As of July, 2021 there are three different COVID-19 vaccines available in the United States. They use different approaches and they are created by companies using different recipes and processes. Understandably, the different vaccines have different side effects. In deciding if a vaccine is right for you, its essential to also consider WHICH vaccine is right for you. The three vaccines available were created by three different groups: Moderna, Pfizer and Johnson&Johnson/Janssen. Below are side effects to be aware of for each of the vaccines.

Inflammation of the heart and its covering (Myocarditis and pericarditis) after COVID-19 vaccination are rare. As of July 12, 2021, after giving more than 320 million doses of the vaccines, the CDC has received 1,047 reports of myocarditis or pericarditis. This happens for about 1 out of 300,000 shots. Its most common among men between age of 11 and 30.