SuperKids Ask a Scientist

Plants grow in two directions, developing both "shoots" and "roots".

"Shoots" consist of stems, leaves, and even flowers, and are responsible for taking sunlight and CO2 from the air and turning it into food and nutrients. Shoots grow at the tip of a plant, so the youngest part of a plant is the highest part above the ground (think of a tree, where the trunk you can touch is the oldest part while the leaves at the top are the youngest).

Roots grow underground to anchor the plant, capturing water and minerals from the soil, and working to store food. Similar to the shoots, root growth is also lead from the tip (imagine the root wearing a hard hat that helps it burrow into the soil in search of water and nutrients).

Like animals, plants have a natural cycle or rhythm, allowing them to grow, flower, and hibernate, based on the signals provided by their natural habitats. The most important signal is the amount of light a plant receives. This is most notable in the spring, when days become longer, more sunlight (and warmth) allows plants to begin to flower after a winter of hibernation.

When a virus enters a cell, it immediately makes as many copies of itself as possible. When doing so, mistakes happen based on the sheer volume of copies being made (think about any time you're writing a thank you card - even though you know what to write because you've written so many, every once and a while you make a spelling error or forget a word). Smaller viruses (single stranded RNA) mutate faster than larger viruses (double-stranded), as their replication occurs quicker. Mutations can also occur when a virus fails to or lacks the ability to repair the mistake.

When a mutation happens, three possible outcomes occur. 1) Nothing happens - the mutation had absolutely no effect. 2) The virus benefits from the mutation (i.e., it can spread faster, evade immune systems better). 3) The virus is harmed by the mutation (i.e., it has a shorter life span, it can no longer spread between certain species).

Mutations are not unique to viruses - we see mutations like this in humans throughout history. Harmful mutations can lead to cancer, while beneficial mutations can lead to resistance to various diseases (such as malaria).

Unfortunately, there is nothing we can do to prevent mutations in viruses - this is evolution occurring in real time. However, we can take steps to limit the spread of viruses (and thereby limit their opportunities to replicate and mutate) by practicing good public health habits, such as washing your hands, wearing a mask/limiting interactions with others when you are sick, and getting regular boosters against the flu and COVID-19 (to make yourself inhospitable to those finnicky viruses).

What a great question! Plants do not breathe, but they do capture air through their leaves to help them make food! Plants do not have lungs. Instead, they have small openings in their leaves known as "stomata" which can open and close, allowing carbon dioxide to enter the leaves and oxygen to be released. Plants are also capable of capturing air through their roots, using their "root hair" to find oxygen in the soil.

They do! Protein is a vital part of any animal's diet. However, the types of proteins they eat vary depending on the animal.

• Herbivores (such as giraffes, kangaroos, cows or rabbits) get their nutrients from plants.
• Carnivores (such as lions, crocodiles, or eagles) get their nutrients by eating other animals.
• Omnivores (such as bears, chickens, or humans) find their nutrients eating both plant and animals.
• Insectivores (such as hedgehogs, armadillos, or frogs) find their nutrients eating insects.
• Detritivores (such as earthworms, dung beetles, or sea cucumbers) get their nutrients by eating decomposing materials (like compost).
• Meat has a higher amounts of protein than plants, but animals have adapted to get the most protein out of their food, regardless of their diets.

Greetings from across the pond - with such an important question!

Vaccination is a very good thing. Vaccination helps us protect ourselves, our families, our friends, and even people we haven't met. It is the best defense we have against COVID, because it trains our immune system how to recognize and defeat COVID before it can make us terribly sick. Some of our other readers have wanted to learn more about how this works, so feel free to read their questions and answers if you want to learn more about how vaccination works.

As for the pain that is sometimes seen when people get vaccinated, that is a real and expected side effect! Shots in general can cause pain, simply because we introduce fluid (the liquid that exists in the shot) into a space that doesn't have room for all of it right away. Think about rush hour on the subway - if a car is full of riders when it arrives at the station and more people try to board, it gets super crowded and hot and uncomfortable; a shot is the same way. The muscle tissue is at it's ideal "crowdedness" level - introducing the shot is like more commuters squeezing on. Over time, a few commuters disembark and the car becomes more comfortable. Same with the shot - over time the fluid will be absorbed into the body and the muscle returns to it's happy natural state.

Other reasons people may have pain in the area of the shot is often caused by the immune response that happens. Our bodies are great at recognizing foreign things, so pain, redness, and heat are all examples of the immune system showing up to defend the body against potential dangers. In the case of the vaccine, this is the moment when the anti-COVID training begins!

Great question - with a very straightforward answer.

YES! The SARS COV-2 virus has been isolated.

As to who first found it and when, that's a little harder to pinpoint - a combination of highly collaborative science means lots of people were involved (not just one person alone) and the time to publish peer-reviewed articles means there is a delay between when something is discovered by a scientist and when the science is deemed sufficient to share with the public (peer-reviewing science before it's published confirms people in the scientific field support the evidence presented in the paper).

The genetic sequence of SARS COV2 was discovered very rapidly, with publications citing the structure as early as February 2020 (read more here: https://doi.org/10.1038/s41586-020-2008-3).

By March and April 2020, scientists had determined the crystal structure of the SARS COV2 virus, published by the Protein Society and in Science (read more here: DOI: 10.1002/pro.3873 or here DOI: 10.1126/science.abb250).

There is a beautiful paper published in CELL in the fall of 2020 that uses multiple novel imaging techniques to show the virus in very high detail in ways that are more easily visualized by the general public (you can find it here: https://doi.org/10.1016/j.cell.2020.09.018)

All of this is incredibly important, because without identifying the virus, we would have no way to screen for COVID (very hard to test for a disease if you don't know what the disease looks like) and no way to develop a vaccine. Good news - in one of the largest collaborations in history, scientists came together to share everything they learned about the virus in real time, allowing for rapid identification of the disease, easy screening techniques, and multiple highly effective vaccines.

Really great and really important question!

To understand why it hasn't stopped, we first need to understand why it happens. Viruses need a place to live, and it turns out that the human body is an ideal location - we are warm, we are constantly taking in lots of food and nutrients, and we have lots of cells that can be reprogrammed by COVID to make lots more copies of the virus. As there are more than 7 billion humans on the planet, that means there are potentially 7 billion homes for the COVID virus to spread and make a home, which is bad (especially because of how sick people get when the virus moves in).

The good news is that the COVID vaccine works really well at making sure your body is no longer a safe place for the virus (once vaccinated, your immune system will recognize the virus as dangerous and kill it before it can set up shop and make copies of itself). For every person that gets vaccinated, that is one less home for the virus and eventually, there will be so few places for it to survive, it will only exist in remote locations in nature, rather than our neighborhoods and schools and homes.

Current data (as of September 25, 2021) show that 33% of all humans are fully vaccinated, with an additional 12% at least partially vaccinated, meaning 45% of the WORLD is vaccinated and protected from COVID (all in less than one year since the vaccine became available to the public). However, that means that 55% of people are still "safe" homes for COVID to enter, infect, and spread. Scientists believe that we need to reach at least 70% of fully vaccinated people before COVID will really struggle to remain and spread in the population, so until then, the best thing you can do right now to help the community reach that number is get vaccinated, wear masks, wash your hands, and help eliminate places COVID-19 can exist.

Great question. We have previously talked about how to decide what type of vaccine to make courtesy of a question from Nikita, a middle school student (see our answers further down the page), so we will use this opportunity to talk about vaccine manufacturing.

Traditional vaccines use a process like this:

• Viruses are generated (using bacteria, cells, eggs, etc as homes for the virus machinery to replicate itself)
• Viruses are harvested and purified from their "hosts"
• Viruses are inactivated (chemically, through heat, etc. so that they cannot cause an active infection, but will still be able to trigger an immune response)
• Vaccines are formulated from the virus (any additional additives, stabilizers, etc, like shuttle viruses or lipid nanoparticles that create the envelope to carry the vaccine into humans)
• Vaccines are subject to MANY quality control tests (checking safety, potency, purity, sterilty, and more)
• Vials are filled with vaccine dosages
• Vials are stored at specific temperatures (dry ice, standard refrigerators, room temperature, etc to ensure they remain safe before being administered to a patient)
• Vials are packaged, recorded (documentation to ensure each batch can be traced), and transported to distribution sites (doctors offices, pharmacies, clinics, etc)

Should you desire a more detailed overview, check out this publication by Gomez and Robinson which can be found here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7152262/pdf/main.pdf

Two of the most notable COVID-19 vaccines, the mRNA based technologies from Moderna and Pfizer, use a slightly different approach. Their generation does not require bacteria - instead a small portion of the COVID virus (commonly known as the "spike" protein, which is the highly identifiable "jacket" the virus wears when it enters a system) is chemically synthesized and then subject to the formulation stage. As it is not cultured in a live host (eggs, etc), it does not need to harvested, purified, or inactivated. When injected, our bodies read the spike protein blueprint (RNA), create more of it, and then our immune system recognizes it as foreign and attacks. Later, if we are exposed to the whole virus, our immune system recognizes the spike protein and is primed to defeat it.

Hi Prisha-

Good question (and welcome to our Australian readers!)

When COVID-19 ends depends on how quickly we can get people vaccinated. Viruses need somewhere to live (a host, like a human), and by getting a COVID vaccine, you ensure your body is not a safe place for that virus (your immune system will recognize it as dangerous and kill it before it can replicate itself). For every person that gets vaccinated, that is one less home for the virus and eventually, there will be so few places for it to survive, it will only exist in remote locations in nature, rather than our neighborhoods and schools and homes. Generally, scientists believe at least 70% of a group of people need to be vaccinated to prevent the spread of a given disease; however, it is still unclear if 70% is high enough for COVID-19 or if even more people will need the vaccination. The best thing you can do right now to help the community reach that number is get vaccinated, wash your hands, and help eliminate places COVID-19 can exist.

Hi Yashika-

Good question!

We currently know of more than 30 unique coronaviruses, some of which can infect humans, while others infect mice, hedgehogs, or bats. There is no current way to completely remove these viruses from nature - it would be similar to asking if we could remove all rosebushes from the world. Somewhere a rose would continue to bloom, just as a coronavirus would continue to survive.

However, in terms of reducing the dangers of the coronavirus COVID-19 that we are experiencing, the quickest way for things to become safe/life to resume many of the activities we did before 2020 is to get vaccinated. Viruses need somewhere to live (a host, like a human), and by getting a COVID vaccine, you ensure your body is not a safe place for that virus (your immune system will recognize it as dangerous and kill it before it can replicate itself). For every person that gets vaccinated, that is one less home for the virus and eventually, there will be so few places for it to survive, it will only exist in remote locations in nature, rather than our neighborhoods and schools and stores.

Hi Nina-

What a good question!

Cancer, in it's simplest definition, is uncontrolled growth. Cancer occurs when cells grow beyond their expected locations and are not stopped by the protections the body has in place to monitor and control normal cell activity. Example: normal cells will grow until every cell is touching a neighbor cell (such as in a petri dish), and then once there is no more free space, cells will send a signal saying "stop growing, there's no more room for any of us". In cancer, that "stop" signal is lost and cells will keep growing, regardless of how many neighbors they have or how little empty space exists in the dish; they can even start growing up and piling on top of each other.

How cancer starts:

Cancer can start in a number of ways, but it is mainly considered a disease of old age. The cells in your body are constantly making more of themselves (to replace old or damaged ones). The longer you live, the more copies your cells have to make of themselves, the more chance there is for something to go wrong (like making a typo in an email). Copying errors can be random, or caused by the environment (things like tobacco smoke, pollution, radiation, and ultraviolet rays), or genetic.

Some of these typos cause cells to do things like grow forever (even when the body says it doesn't need any more of those cells), create it's own food sources (why wait to get nutrients the cells have to share with others when they make their own), or encourage cells to move to places they shouldn't (like when a lung cell goes rogue and decides to move to the brain).

When is the first time cancer was ever observed in human history?

The first documented case of cancer in history goes all the way back to 1500BC in Egypt - written on papyrus were notes about tumors found in breast tissue.

Yes, the two vaccines currently approved for use in the US are safe. Despite the fast time from design to delivery to patients, this was a massive undertaking done at the highest standards of vaccine development.

• Scientists built on research they were already doing, including SARS vaccines designed back in 2004, mRNA vaccines which were already in the works, just not widely used, etc.
• Different teams of scientists designed two unique vaccines (Moderna and Pfizer), and found that when they were tested in clinical trials (30,000 people and 44,000 thousand people respectively), each achieved more than 90% efficacy. This is a great example of a study yielding high confidence - if two studies done independently reach the same conclusion, we can feel confident in their results.
• In these trials, the vaccines virtually eliminated hospitalizations and death from COVID-19. This is significantly safer than the risk from contracting the disease itself.

The only "downsides" to the vaccines are their side effects - but the good news is that these are right in line with the side effects associated with vaccines for other diseases, even the annual flu shot; things like pain at the injection site, body fatigue, muscle soreness, etc. If you want to learn more about the side effects to expect, the CDC and FDA have some great information on their websites:

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/expect/after.html
https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/moderna-covid-19-vaccine#additional
https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/pfizer-biontech-covid-19-vaccine#additional

There's a formula for calculating vaccine effectiveness (VE):

VE = (Risk for unvaccinated group - Risk for vaccinated group)/(Risk for unvaccinated group).

Example: if we have 170 trial patients infected with COVID, 162 who received a placebo and 8 who received a vaccine, the calculation would be (162-8)/162 = 95% effective.

This number indicates that in the trial, there was a 95% reduction in confirmed symptomatic COVID cases among the vaccinated group, from the number that would have been expected if they had not been vaccinated.

In a sense. These people are still observing their local COVID rules (wearing masks, maintaining 6 feet from others, washing hands), but they are not just sitting at home in quarantine. They also are not actively going out like they would have, pre-COVID.

Every trial phase has control and treatment arms, where the control patients are receiving a placebo. That means these control patients are receiving an injection of saline. Interestingly, this is a triple blinded study. That means the subjects don't know if they're getting the vaccine or the placebo, the doctor administering it doesn't know, and the scientists looking at the results don't know. The only people who get to see the true full data are the people on the data monitoring committee to prevent any potential bias or data manipulation.

A cure? Not exactly.

A treatment/preventative measure? Absolutely.

A cure is defined as something that ends a condition. Example: tweezers are a cure for a splinter. Once the tweezers have been used, the splinter is removed and gone forever.

A treatment is something that helps manage the symptoms of a disease, but doesn't necessarily remove the disease completely. Example: an inhaler is a treatment for asthma. People can take the inhaler any time they feel the symptoms of asthma coming, but taking the medication won't prevent their asthma from coming back again. Lots of potential treatments for COVID-19 are being studied and/or developed, and a few have been approved for limited use, like dexamethazone, a steroid.

A preventative measure is something that people take before they get sick to protect them from getting sick. Example: the new COVID vaccines recently announced by Pfizer and Moderna. People will receive the vaccine, their bodies will build up defenses in their immune system, and then if the person comes into contact with COVID, their body will fight it off before it can take hold and do any damage.

Great question.

A therapeutic is any treatment for a disease or symptom. It can be treatments like a pill, a steroid, an injection, a small molecule, or an antibody.

A vaccine is a preventative measure, designed to protect a person against becoming sick. Examples include vaccines for smallpox, polio, and the flu.

[Not to confuse the issue, but there is a 3rd category, called therapeutic vaccines. These are designed for use after someone is already infected, and aim to stimulate the individual's immune system to more effectively attack the infection. Examples include the rabies vaccine, and some vaccines for certain cancers.]

This feels like a question that needs one more sentence of context. Regardless - we've tried to answer it anyway! (If this was your question and you'd like to elaborate in a few more words should our answers not be fulfilling, let us know!)

Letters as symbols, notations, and shorthand:
Greek letters are prominent in the sciences (particularly chemistry, physics, astronomy, and biology), both as shorthand and for differentiating various proteins and chemicals based on their orientation. Some examples include:

• alpha represents angular acceleration in physics
• lambda is the shorthand notation used for microliter in biology
• delta is used to represent percent error or difference
• mu is one of the most common in biology as it is a unit of measure such as microns/micrometers (um) or micromolar for molarity (uM)
• some classes of proteins are differentiated by combinations of greek letters, such as members of the integrin family, like member integrin alpha 2 beta 1 that should not be confused with integrin alpha 6 beta 4

Letters as a form of correspondance:
Many scientific journals have a type of publishing format known as "letters", also referred to as "communications", which are short articles with data that editors feel should be rapidly published for the public to see, rather than waiting to complete the breadth of experiments and data needed for a full scientific "article". These are not the same as "Letters to the Editor", which are opinion editorials.

For example, Nature Letters can be found here: https://www-nature-com.eu1.proxy.openathens.net/nature/articles?type=letter

As Elle Woods so effortlessly pointed out in Legally Blonde, "Exercise gives you endorphins. Endorphins make you happy." The thing is - she's not wrong. Exercise has been scientifically shown to decrease stress, anxiety, and depression while also increasing happiness, learning ability, and even your ability to sleep. Looking forward to your school year, putting an emphasis on physical activities may be a way to balance not only your physical health but also your mental health.

COVID-19 has certainly put a damper on many forms of exercise, leaving a lot of us trying to find new ways to still get that endorphin boost. If going for walks around your neighborhood or riding your bike aren't feasible or aren't sufficiently fun or exciting enough, now is the time to branch out. If available, try finding some new classes online like through the YMCA or your local gym. Unlike being in a class at the gym, no one can see how inflexible you are or how bad you are at counting music when working out online - so no excuses!

Digital workouts not your thing?

The home is ripe with options for making up your own styles of workouts.

• Example 1: Find a deck of playing cards - assign each suit a type of exercise (hearts are pushups, clubs are lunges, diamonds are planks, and spades are burpees, etc.) and the number that comes up are either the number of reps or 5x the number of seconds you do the exercise.
• Example 2: Using the letters of the alphabet, walk around your house in the format of an animal starting with the same letter (A - Ape walk; B- Bear crawl; C - Crab walk; see how far through the alphabet you can get).
• Example 3: if working out by yourself isn't cutting it, reach out to your local animal shelter and see if they are accepting volunteers to walk their dogs. COVID-19 may have affected these policies, but this is always a great way to find a walking buddy who will definitely be excited to walk anywhere you want to go at any time - and you don't have to worry about whether or not they remembered their mask too.

From a mental health perspective, remember that you definitely are not the only one going through things right now. If it's in your bandwidth, set time aside each week to have a phone call or a Google hangout or a gaming session with your friends. Talk about anything not related to COVID-19 - who found the best new waffle recipe, who's reading the worst book, who's wearing the best sock combination, something positive and pleasant to debate. If you're not mentally up for talking to anyone after a day/week of classes, that is okay too. The important thing is to try to stay engaged with something - even if it's just classes.

If you need more ideas, Harvard has a really nice collection of videos and blogs about staying healthy in the time of COVID-19 that could also be a good starting point for some of your own research: Coping with Coronavirus

If you come up with any of your own great solutions that you want to share, feel free to write back in to Ask A Scientist and we'll share your discoveries with our other readers!

What a great question (and one lots of scientists are trying to answer right now)!

The short answer? We're not sure.

The long answer? There are a lot of things we need to think about to try to answer both of these questions.

1. How long does a virus live?
   One of the key features about viruses, including COVID-19, is that they need a host (a body) to survive. If they don't have a home, their existence is generally only a matter of hours (up to a week at most). Therefore, if we can build up enough immunity in humans, we can essentially remove us as a possible host for the virus.
2. When will this main outbreak of COVID-19 end?
   Right now in the United States, we are seeing increasing numbers of confirmed cases and hospitalizations in many areas of the country, making it less likely COVID-19 will end soon. Some other countries, like New Zealand and South Korea, have managed to control the spread of COVID-19 and have kept their number of cases low, giving hope that this is something we may be able to control through good social practices.

   • Is it over when we have a vaccine? How long do vaccines take to generate? How long to innoculate a population?

     Unfortunately, making a vaccine is a very time-intensive process - starting from identifying what part of the virus the vaccine will target, to the testing of a candidate vaccine in patients (it's really important to study all the of the possible side effects of a vaccine to make sure that it targets just the virus and not something else important in the body). One of the fastest vaccine developments to date was the mumps vaccine - and that took 5 years.

     On the plus side, this is one of the largest and most rapid attempts to identify and mass produce a vaccine in history! Scores of companies are working to understand COVID-19 and design a treatment to protect against it. As of the writing of this answer, several companies have already moved to the last stage of clinical trials with their vaccines - testing to see if their treatments prevent patients from catching COVID-19. If successful, we could see vaccine production possibly by the end of the year.

   • Is it over when we reach herd immunity?
     Herd immunity is when enough of the population has built up immune resistance to infection (by becoming infected and recovering, or by receiving a vaccine) such that even if someone without resistance does get sick, they won't be able to easily spread it. Think of this like when you're at a birthday party passing out slices of cake. If enough people have a piece, if someone hands them another slice, they can't take it and the person trying to pass the piece has to just hold on to it. Current studies say we are likely at least a couple of years away from reaching herd immunity, though this could happen faster with a vaccine.

3. What can we do to help speed this up?
   Wear a mask. Wash your hands. Don't touch your face or eyes. Minimize your social contacts. Help prevent the spread of COVID-19. The sooner enough people do this, the sooner life will become more normal.

Great question! Some of the datasets I watch include the following:

• The COVID Tracking Project [breaks down daily tests, cases, current hospitalizations, and deaths in easy to follow graphs]
• DIVOC Interactive Visualization of the Spread of COVID-19 [similar, but with international as well as US data]
• NCOV2019 [daily interactive covid tracker, made by a high schooler!]
• BiopharmaDive Coronavirus Frontrunners [keeps track of the big current vaccines in trials with good breakdowns of each vaccine type]
• Harvard Coronavirus Resource Center [constantly updated general information including covid symptoms, risk factors, mental health risks]

Simply put, "novel" means "new".

Scientifically speaking, any time a virus (or bacteria or disease) is discovered that hasn't been previously identified, it is classified as "novel". Though humans have been exposed to coronaviruses before, and even SARS-based coronaviruses, this is the first time we have seen/experienced/contracted SARS-CoV2. Hence, it is novel!

Short answer - we create something harmless that the human body will mistakenly recognize as the disease virus, and then the body builds up an army of antibodies that can later attack the real virus if it enters the body.

Details.... There are many things scientists have to think about when making a vaccine.

1. What kind of virus is the vaccine targeting?

   Viruses are often classified by their genome (their DNA) - is it double stranded DNA (like humans), single-stranded DNA, double-stranded RNA, or even single-stranded RNA? Determining the genome format helps understand how the virus replicates (reproduces) and therefore how to target it.

   Viruses cannot replicate by themselves - they need a host cell and can only infect specific species (or even a single tissue within a species). For example, swine flu can infect pigs and humans. Other viruses can only infect a single type of bacteria known as E. coli. Understanding the type of cell targetted by a virus helps guide vaccine development.

2. Have we ever made a vaccine for a virus like this before?

   One of the great features about science is that it builds on itself - once the field has learned a solution, scientists can use it again rather than having to start from scratch. Based on identifying the features of the virus, scientists have a place to start when designing vaccines - like in the case of COVID-19 [SARS-CoV-2] vaccines, many companies are looking at vaccines developed for the SARS [SARS-CoV] outbreak in 2003.

3. Who is going to need this vaccine?

   To make a successful vaccine, it is very important to identify both the burden of the disease and the target population. This means understanding how big of a deal is this disease and how many people are likely to get it. A common example is the flu shot (also known as the flu vaccine). According to the CDC in 2018, 35 million Americans had flu symptoms - that's more than 10% of all Americans. 11 million were under 18 years old, 12 million were between 18-49, and 12 million were over 65. There is a clear example of disease burden (more than half of these patients saw a doctor because of their symptoms) and population (all ages were affected).

4. How do you make the vaccine?

   While the first example of vaccines dates back to 1796 (when a doctor named Edward Jenner scraped pus from a wound on a milkmaid's hand and then injected it into an 8-year old boy to inoculate the boy from smallpox), things since then have become significantly more controlled and regulated! The type of vaccine you want to make will determine the method that is used.

   Vaccines against things like polio or measles use "live attenuated viruses" which are viruses that have been chemically weakened so they can't cause disease, and are then grown in animal cells in plastic petri dishes.

   Vaccines against things like the flu (influenza) grow the virus in chicken eggs where it can quickly make more virus. Once removed, it will be chemically inactivated so the virus cannot continue to infect cells but maintains its shape so the body can recognize it as foreign and attack it.

   Vaccines against things like Hepatitis B use "recombinant or subunit vaccines" which combines a small part of the viral DNA (usually the surface markers that identify a virus as a virus) with a second non-dangerous virus that is used to shuttle that virus DNA piece into cells. This combination virus is then grown in animal cells and response proteins that are released by the cells are collected to be used as a vaccine.

   Two vaccine types that are currently in the news around COVID-19 include DNA and RNA vaccines. Similar to recombinant vaccines, DNA vaccines use part of the virus (genomic DNA) that will cause the immune system to respond, put into bacterial cells where the viral gene can be grown in massive quantities, and then can be put into animals. The potential advantage of a DNA vaccine is that they usually only require a single dose and because they haven't been weakened or inactivated, they more closely resemble the actual virus. RNA vaccines follow the same principle, but use mRNA (messenger RNA) in place of DNA, with the added benefit that mRNA cannot interact with the host's DNA and cannot replicate on its own.