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What are Monoclonal Antibodies?

According to this article by the manufacturers of Rituximab, or the brand name of Rituxan, this prescription drug is used to treat adults with Non-Hodgkin’s lymphoma and Chronic Lymphocytic Leukemia. This medicine works through monoclonal antibodies which are proteins that attach to antigens (or foreign substances in the body) and mark them for the immune system to kill them or cells infected with them. Monoclonal antibodies in particular are made in labs to target a specific antigen, and make copies of it by fusing B cells (capable of making antibodies) and myeloma cells (which grow indefinitely). Different monoclonal antibodies are made using different combinations of mouse/rat and human proteins. They collect these proteins by extracting spleen cells from the subject.

More About Rituximab

According to this article in medicinenet.com, Rituximab targets CD20, which is a receptor on almost all non-Hodgkins Lymphoma cells. The antibodies initiate lysis (disintegration) of these tumor cells when they attach. It can also prevent the growth of more tumor cells in some non-Hodgkins Lymphomas. This will then result in the killing tumor cells and hopefully remission for the patient when in combination with chemotherapy medicines. The drug will effect the acquired immune response of patients by depleting the numbers of B cells in lymph nodes and circulating through the blood. You could therefore say that this dug negatively affects the immune system, and that too much of the drug can lead to serious complications related to the lack of immune response.

More Information on the Medicine

Side effects of taking Rituximab include:

• Infusion related reactions (such as hives, itching, swelling, weakness, dizziness, etc. )
• Severe Infections
• Fatigue
• Body aches
• Runny nose
• Difficulty breathing
• Flushing
• Decreased blood pressure
• Tiredness
• Nausea
• Vomiting
• Aching joints hours after infusions
• More frequent upper respiratory tract infections
• Severe skin and mouth reactions (ulcers, peeling skin, blisters)
• Hepatitis B reactivation
• Progressive Multifocal Leukoencephalopathy
• Tumor Lysis Syndrome (leading to kidney failure or abnormal heart rhythm)
• Heart Problems
• Kidney Problems
• Stomach and serious bowel problems

However, according to his article, this drug is commonly used to treat B-cell non-Hodgkins Lymphoma which has side effects which may include:

• Swollen lymph nodes
• Abdominal pain and swelling
• Coughing
• Chest Pain
• Trouble Breathing
• Fever
• Unexplained weight loss
• Night Sweats
• Persistant fatigue

As listed in the list of side effects for taking Rituximab, one of the complications includes Hepatitis B virus reactivation. According to this article in the World Journal of Hepatology, this can occur because the medicine is depleting B cells with CD20 and therefore immune globulin production which accelerates Hepatitis B replication. Furthermore, the effect on T cells that Rituximab has will further exacerbate liver problems with Hepatitis B.

What do we know currently?

According to an article in Scientific American, the World Health Organization’s Solidarity II is a study across more than a dozen countries which is examining antibody data from these populations. This is important to begin developing knowledge about the antibody response to COVID-19 and how nations can better protect their citizens. Researchers are currently trying to answer two questions: How long do COVID-19 antibodies remain in the blood? And whether or not they protect against reinfection. This will allow them to determine the types of vaccines they can produce and whether herd immunity is a viable option. Many scientists are studying other forms of Corona Viruses to find answers, because long-term data at this point is lacking. They are hoping that people make neutralizing antibodies, because vaccines would be much easier to develop if that was the case. Hopefully this data can be collected quickly so we can begin to combat this deadly virus sweeping the world.

How does the antibody response work?

According to an article in Diazyme, the test for COVID-19 RNA genomes, or the test for a current COVID-19 infection, is currently producing many false negatives (some say as many as 1 in 3 patients tested). This obviously creates a dire need for IgM/IgG serological tests. IgM/IgG serological tests test for the presence of antibodies in the blood of patients, and provide a much more reliable way to to test for current and past infections. Unfortunately with COVID-19, the human antibody response to it is very slow therefore it may take up to 3 days after the onset of symptoms to be able to detect antibodies. If someone were to only have IgM titers, this would mean that the blood was taken from the patient during the primary or first infection from the virus, which is usually 7 days after infection with COVID-19. If the patient came back with both IgM and IgG titers, this would mean that the patient would be starting to recover from their primary infection, which occurs around 14-21 days after infection with COVID-19. Having primarily an IgG titer would mean that the patient has fully recovered from the initial infection. If we could determine who was IgG positive, this would mean that they were immune to reinfection and unable to infect others anymore.

What do I think?

I think that emerging research regarding the antibody response to COVID-19 gives much hope to the search for immunity and vaccinations against this virus. I also feel much more informed on testing after doing research for this blog. I now know that it requires a combination of IgM/IgG serological tests and Reverse Transcriptase tests to correctly diagnose COVID-19. I think this could possibly create a problem because the cost of testing is so high and having two tests as opposed to one raises prices even higher. I can’t imagine this pandemic getting any better until this important research has been done or a vaccination has been developed.

What we know

According to this article in the New York Times, the old tuberculosis vaccine may be effective in bolstering immunity and therefore helping to prevent COVID-19 infection. As of today (April 5th, 2020), scientists are currently trying test the vaccine against COVID-19. The vaccine is known as the Bacillus Calmette-Guerin vaccine and is still used in many parts of the developing world to prevent respiratory infections in infants. Apparently the vaccine trains the immune system to recognize many different types of infections better. In Australia a randomized controlled trial was done by administering this vaccine or a placebo to thousands of health workers working with corona virus patients to see the results. The vaccine is intended to shorten the time and lessen the severity of the sickness, rather than prevent individuals from being infected at all. I think that news of this vaccine potentially lowering the risk of death with corona virus infection may create a sudden demand for this vaccine in the general population, despite health workers needing it the most. I believe that when there is proof of an effective vaccine, we may see only the richest and most privileged members of society receive the vaccine first, further exacerbating the detrimental effects this pandemic has on underprivileged communities.

Why the Tuberculosis vaccine?

Despite the Tuberculosis vaccine targeting TB in particular, evidence from the previous decade has shown that the vaccine also reduces viral illnesses, respiratory infections, and sepsis. This points to the fact that the vaccine potentially bolsters the body’s immune system, making it more effective in fighting off deadly infections such as COVID-19. I also think that this vaccine is a great starting point that could hopefully buy scientists some time as they try to discover a vaccine specific to COVID-19 that would further prevent infection. As many articles online warn however, it is a bad idea to jump on this preliminary research about the B.C.G vaccine because it is still unknown whether the vaccine could in fact increase your risk of acquiring COVID-19 or dying from it. It is stressed that this is just preliminary research and too early to determine what kind of effect it will have on individuals in terms of COVID-19.

Promising Data

According to this article on Bloomberg.com, research has shown that countries who have mandatory Tuberculosis vaccinations also report fewer deaths due to COVID-19 than countries that do not. In places such as South Korea, Japan, and China, which all have mandatory TB vaccinations, the disease was managed much better than in places which do not have a TB vaccination requirement. According to the same article mentioned above in the New York Times, a randomized trial of 2,320 babies in Guinea-Bissau showed that babies who were vaccinated against TB had a significantly lower death rate among low-birth-weight babies than those who were not. Another worldwide epidemiological study from this article showed that there was a 40 percent lower risk of acute respiratory infections in children who received the TB vaccine. I think that these promising studies give hope to many scientists worldwide, and it is a great starting point for beginning trials in people most affected by Corona Virus.

Dendritic Cell Therapy

According to this article in Nature Communications, Dendritic cell vaccines, in particular type 1 Dendritic cells, are being used to treat cancer patients through immunotherapy. Type 1 DC’s (dendritic cells) have the ability to uptake and present tumor-associated antigens therefore priming effector cells to have the ability to respond effectively to tumor cells. Furthermore, dendritic cells in particular are able to move in between lymphoid and non-lymphoid organs and control inflammation and lymphocyte homing, which are important for long-lasting anti-tumor effects. The vaccines are made of patient-derived DC’s made from isolating hematopoietic stem cells and treating them with cytokines for differentiation and then with TAA’s (tumor-associated antigens). This immunotherapy seems quite promising as it has been proven safe in multiple clinical trials, however, the effectiveness of this treatment falls short when put in vivo due to functional deficiencies in the cells that comprise vaccines. I think that the future of disease-treatment– and potentially cures — lie in stem cell research and technology. When these types of treatments become available for public use and more effective, the limits of previously incurable disease therapies will be non-existent. Having a brother with an autoimmune disease (type 1 diabetes), I find stem cell research and dendritic cell therapies to be extremely important and something I may want to be involved with in the future.

T Cell Therapy for Melanoma

According to this article in DTU Health Technology, ACT, or Adoptive T-cell Therapy is an immunotherapy that works well for patients with malignant melanoma. ACT has currently been tested to see whether or not naive antigen-specific T cells in combination with a tumor-antigen and a toll-like receptor (TLR7) in a liposomal formulation will work for curing cancers beyond melanoma. Findings from this study showed that this formulation did in fact induce antigen-presentation and on APC’s and infiltration of T cells to improve tumor control in vivo. Furthermore, it was found that relapsing tumors had become immune excluded and unregulated immune suppressive mechanisms. I hope that research like this continues to prove the benefits of immunotherapy and the treatment of aggressive diseases such as cancers. I think it is amazing that ACT has already been proven effective for melanoma and it gives me hope for what this means in curing other types of cancers.

How it works, Side effects, Cost?

Dendritic and T cell therapy for various cancers mentioned above works by teaching the immune system to recognize mutated self-cells that are cancerous when they present mutated antigens. Once these mutated cells are recognized, the immune system can eliminate them. This can happen with tumor cells or melanoma cells. The most common side effects of immunotherapy include skin reactions, flu-like symptoms, and many others such as hormone changes, shortness of breath, weight gain, and diarrhea accrording to this article by Cancer.Net. The cost of these types of therapies averages around $250,000 a year when combing drugs, which is quite common. The cost and side-effects of these drugs seem to be detrimental to me, but almost inevitable given the deadliness of most cancers. Not only would the discovery of more immunotherapies be revolutionary, but also the discovery of how to make them more accessible and safe.

How has my perspective changed?

When I first heard about the corona virus, or COVID-19, it seemed distant and unimportant to my everyday life. In my microbiology class, I learned that it was just another virus that would be handled in similar ways to ones we already know about. I had no idea of the detrimental effects it would end up having across the world and so close to home. Everyday it seems that more and more people I know or hear of are losing friends and family due to this virus. I went to Costa Rica and then Miami for spring break thinking it was all fun and I could tune out all of the news about corona virus, but as I got back home I started overthinking all of the people I had come into contact with other these 2 weeks and all of the public places I could’ve been exposed to this deadly virus. It has made me hyper-aware and constantly worried of people I may be infecting or infected from. The more and more news stories I hear about medical facilities running out of equipment and turning away sick people has begun to terrify me and I no longer see this virus as unimportant or blown out of proportion.

What have I been up to?

Recently, I’ve just been hanging out and living at my friends house who I’ve been seeing since I got back from spring break. I am too worried to go home and see my father because he has several pre-existing conditions such as hypertension and heart disease that makes him vulnerable to the worst effects of COVID-19. My roommate seemed upset that I had been in multiple airports over spring break and did not want me around her too much when I got back, therefore I have basically moved in with my friend. We spend most of our days waking up late and learning new recipes that we eat while watching Jersey Shore (I know it’s horrible) or going on Zoom for classes. I have found it extremely hard to keep up with work because all of my deadlines and class schedules have changed, along with so many different platforms that professors use to update us about it. I wish that I could have one site that all professors used to answer questions or conduct class, but every professor has their own way of handling online courses and it can be overwhelming sometimes. I also find it much harder to be held accountable and pay attention during class when it’s online and I am at home with distractions…I wish I could go to the library or a coffee shop.

Closing thoughts: How am I feeling?

I have been trying to stay positive and look at the bright side of quarantining and social distancing. The weather in Chapel Hill has been beautiful and it’s been so nice to finally have time and flexibility to walk outside and enjoy nature. I also love having more time to sleep and take care of myself unlike during the school year when I am constantly doing something. However, I am very worried about our health systems collapsing in the United States with inadequate testing of the disease, inadequate protective gear for health professionals, and lack of equipment or even space in hospitals for those affected. I know that the pandemic is just getting started in the United States and it makes me wonder what is left to come. I also am feeling great sadness for all of the seniors everywhere who couldn’t enjoy their last few months of college the right way. I am thinking of everyone who is being affected by the virus whether it be losing a family member, losing a job, or losing an important event such as a wedding or graduation. I am looking forward to when this virus begins to be less of a concern and we can all move past it.

What is HPV?

According to an article by the CDC, the Human Papillomavirus is the most common sexually transmitted infection in the United States. There are many different strains of HPV, but some HPV strains cause adverse health effects such as cancer and genital warts. It is spread through vaginal, anal, and even oral sex with someone who carries the virus. The warts caused when HPV doesn’t go away on its own will appear as little bumps and groups of bumps on the genitals. Some people who carry HPV may not show symptoms at all but can still transmit it to sexual partners. I think this is a big reason why everyone needs to wear condoms no matter what the circumstance. I also think it’s important for sexual education courses to emphasize the point of asymptomatic carriers, safe sex, and routine check-ups. 

HPV Vaccine

There are six types of cancer caused by two strains of HPV: Cancer of the cervix, penis, vagina, vulva, back of the throat, and anus. According to the CDC, more than 9 of every 10 cases of cervical cancer is caused by HPV and cervical cancer is one of the leading causes of death for women in the United States every year. Thankfully, a non-infectious recombinant vaccine prepared from virus-like particles called the 9-valent HPV vaccine protects healthy individuals from contracting the cancer-causing strains of HPV. This vaccine is recommended for 9 through 15 year olds who have not yet started being sexually active. Even sexually active individuals can benefit from the vaccine by protecting them from contracting more dangerous strains of HPV in the future. I think that the HPV vaccine has completely revolutionized the STD/STI prevention measures and is saving thousands of people from genital warts, cancer, and even death. I also think it’s important to give children this vaccine early before they begin being sexually active to provide them with maximum protection. Furthermore, even males are not the ones experiencing such severe health effects from the infection, it is still just as necessary to vaccinate them to prevent transmission with female sexual partners.

Current issues surrounding HPV-related disease

According to this article by Belotserkovtseva and Mayer, a survey done with 14-17 year olds in KhMAO-Ugra, Russia, found that 25% of these adolescents had already had sexual experience and did not know methods of contraception or “safe sex”. Furthermore, about 52.7% of these adolescent girls had HPV and 37.9% had oncogenic types, or types that cause cancer. This problem in Russia is responsible for cervical cancer being the number 1 type of cancer in women under 30 years old. I think that it is necessary to spread information about the HPV vaccine to all parts of the world in order to protect a vary vulnerable part of the population: young women. According to another article in JAMA looking at oral HPV herd immunity in unvaccinated US male populations, it was found that vaccine-type HPV prevalence decreased 39% from 2009 to 2016 whereas nonvaccine-type oral HPV prevalence remained the same. This goes to show that herd immunity for HPV strains prevented by the vaccine is working well. We all need to continue vaccinating ourselves and our children to protect every individual from such adverse health effects. 

What is a superbug?

According to this article in WebMD, people often refer to “superbugs” as bacteria that has become resistant to multiple antibiotics. Doctors will use the term “multidrug-resistant bacteria”. According to this article in Medical News Today, these drug-resistant bacteria infect anywhere from 2-3 million people in the US per year and kill around 23,000. Some various forms of drug-resistant bacteria that are labeled as an “urgent threat” by the CDC include Clostridioides difficile, Neisseria Gonorrhoeae, methicillin-resistant Staphylococcus aureus, and Carbapenem-resistant Enterobacteriaceae. These organisms are resistant to almost all forms of antibiotics and cause death in the majority of people who get bloodstream infections from them. Furthermore, horizontal gene transfer such as conjugation and transduction allows resistance factors and abilities to be transferred to other bacteria within their bacterial family.

How have we gotten to this crisis point?

The most obvious reason that has created this issue of “superbugs” is the misuse and overuse of antibiotics. Many people believe that antibiotics can be used to treat all types of illnesses, including viruses such as influenza on which antibiotics have no effect. When people use too many antibiotics, their bodies may lose “good” or healthy bacteria that keep them healthy, further creating stronger bacteria and infections. Doctors can also exacerbate the problem by overprescribing antibiotics and sometimes prescribing the wrong ones. When I was in Thailand for a study abroad program, I could receive antibiotics from the pharmacy without a prescription from a doctor, showing that in many places people will self-diagnose themselves and seek antibiotics in the wrong situations. The last problem we face is the gross overuse of antibiotics in animals, particularly farm animals that will be consumed by humans. This creates drug-resistant bacteria in farm animals and eventually humans as well.

What can we do to prevent it?

I find the rise in antibiotic-resistant drugs in current times to be frightening and of utmost urgency to our medical system. In a way, I think it is comparable to environmental issues facing the planet: people are pretending that that issue doesn’t exist because it cannot be seen directly. I think if more people knew the statistics about death and infection from these drug-resistant microorganisms, it may create more concern and action in the public. In order to prevent these issues from getting worse, this article by the CDC recommends washing hands, covering coughs, getting recommended vaccines, and staying home when sick. Other ways to protect yourself and others from antibiotic resistance include taking your antibiotics exactly as a doctor prescribes, never sharing antibiotics with others, safely discarding medicine, and most importantly, never taking antibiotics when they are unnecessary or if a doctor hasn’t prescribed them.

Oral and Inactivated Poliovirus Vaccines

I will begin my blog post by explaining the difference between the IPV, or the inactivated poliovirus vaccine and the OPV, or the oral poliovirus vaccine. Interestingly enough, we will see how the combination of these two vaccines has been used to protect people the most efficiently around the world. According to a chapter in Nester’s Microbiology Textbook, the Salk vaccine, which is now known as the IPV, was developed in the 1950’s which requires multiple injections to receive full protection. This vaccine contains inactivated particles of all three serotypes of the poliovirus. The Sabin vaccine, now know as the OPV was developed in 1961 and uses attenuated strains of the poliovirus to provide immunity. The advantage of this vaccine is its lowered price in comparison with the IPV. To ensure herd immunity, the OPV must be used because of its ability to induce mucosal immunity in the throat and intestinal tract. However, very rarely vaccine-related poliomyelitis (the disease caused by poliovirus) will occur in people receiving the OPV, so it has been phased out in many countries that have achieved eradication. In places where wild-type poliovirus is still present, the OPV is commonly used.

Poliovirus in the United States

According to an article by the CDC, in June of 1996, the ACIP, or the advisory committee on immunization practices, recommended a switch from only OPV vaccination to OPV and IPV vaccination so as to avoid rare, but deadly, vaccine-related poliomyelitis from the OPV vaccines. The last case in the United States from a residing person was in 1979. In the entire Western Hemisphere, the poliovirus was eradicated due to steady immunization from the OPV. In 2000 began the recommendation to use only the IPV in the United States as long as population immunity remained high (through herd immunity) and prevention of importation. Vaccination among children in the United States remains high due to immunization initiatives, particularly by the World Health Organization and other organizations within the United States. Vaccination of children is so important because it will not only affect the child, but also those around them. According to an article from Kidshealth.org, children should receive the IPV in the United States at ages 2 months, 4 months, 6-18 months, and 4-6 years.

Poliovirus Around the World

According to an article in the Bangladesh Journal of Medicine, the oral polio vaccine, or OPV, has been one of the main defenses against in India for the past 30 years. In the last two years however, the IPV or the inactivated polio vaccine is rising in popularity, now acting as the main protection in immunity against the type 2 poliovirus as indigenous poliovirus outbreaks declines. According to an article in The Lancet, vaccine-derived cases of the poliovirus have occurred recently in parts of Africa and the Philippines and an upsurge in cases of the wild-type poliovirus in Pakistan and Afghanistan. I think that hygienic practices and sanitation standards in many parts of the world could also be used to mitigate outbreaks of the poliovirus. I think that the right to water and sanitation can be drawn upon in these areas of the world by citizens to further protect themselves from the virus when the vaccine is less accessible. Health in populations starts at the government and I believe vaccines as well as sanitation fall under government responsibility.

What is the Microbiome?

Unless you happen to take biology classes in college, you may have a limited understanding of what the word “microbiome” means. I had no idea that there are more microbes in our bodies than human cells until my genetics class in college. In fact, I had never even heard the word “microbiome” until I got to college. The microbiome consists of “trillions of microorganisms of thousands of different species” according to an article by the Harvard school of Public Health. This includes bacteria, fungi, viruses, and parasites existing in many different parts of the body such as the mouth, skin, nose, vagina, and gut. The largest amount of these microorganisms exist in our small and large intestines, and these are known as our “gut microbiota”. During birth, babies are first exposed to microorganisms in their mother’s birth canals. As the baby grows up, environmental exposure and diet change and grow their microbiota. Disturbances in the balance of our “good” and “bad” microbiota can result in dysbiosis and higher risk for disease.

How does the Microbiome affect Health

According to an informative slideshow by WebMD, your gut microbiome works to keep your digestive system healthy by keeping “bad bacteria” in check. In other words, most bacteria are what we call “opportunists”, which means they can only flourish when other microbiota aren’t around. In our microbiology class, our professor stresses the importance of balancing microbiota so that opportunists cannot takeover and cause infection. Furthermore, your gut microbiota creates chemicals that respond to different foods we eat that can have different effects on many parts of the body. For example, when we eat red meat or eggs, bacteria in our gut makes TMAO which can help cholesterol build up in our blood vessels and can also lead to kidney disease. Even our brains are affected by our microbiota as studies have shown they play a role in emotion regulation and information processing like sights and sounds. Another role that your gut microbiota plays in health is through weight regulation and appetite control.

Conceptually, we should view these microbes as a newly discovered organ, weighing slightly more than our brains and nearly as vital.

– Tim Spector of BBC Science Focus Magazine

What Can We Do?

According to an article by BBC science focus magazine, the microbiome inside of human guts should be viewed as a “newly discovered organ” due to its vitality within the human body. Interestingly enough, research into the microbiome is relatively recent, and evidence of their importance to the human body is still being discovered everyday. Further, every single person’s microbiome is different and has a significant and unique impact on your health. In animal tests and human studies, researchers have found that we have a lower risk for allergies and disease the more diverse our gut microbiome is. Some things we can do that increase our gut microbiome diversity include eating a high fiber diet, a variety of fruits and vegetables, fermented foods, small amounts of alcohol, avoiding artificial sweeteners and antibiotics, touching animals and trying not to be “hygiene obsessed” (Spector, 2020).

This Year’s Flu Vaccine

According to a recent article by the CDC, this year’s flu vaccine targets 4 different antigens, or strains of the influenza, so it is a quadrivalent inactivated influenza vaccine. It was grown in cells, as opposed to eggs. The FDA has approved a slightly higher dose this year for children from six to thirty-five months old, as opposed to previous year which allowed only half of the normal dose to be administered to children this age. The CDC also warns to receive the vaccine closer to “flu season”, stating that July or August vaccination may be too early and lead to reduced protection later in the season. Unfortunately, it is slightly too early to predict the effectiveness of this year’s vaccine because researchers must compare infection rates of those unvaccinated to those that were vaccinated. Furthermore, the two factors that determine the likelihood that the flu vaccine will protect an individual are 1) individual characteristics such as their age and health and 2) the similarity between the flu vaccine and the flu virus being spread (CDC, 2019). Getting a flu shot is not only important for protecting yourself, but also for protecting your community and others who may not be able to be vaccinated. I think that it is interesting how every year, the flu vaccine protects against new forms of the influenza virus and has specific recommendations depending on your age. For more information, look up recommendations on google to learn where, how, and when is the most effective to receive your flu shot.

Forget about the Coronavirus

In an article by CNN, the author warns that the real threat to worry about in 2020 is influenza, despite current fears and media coverage of the new coronavirus (2019-nCoV). Influenza has already killed 10,000 people just this season (2019-2020) and at least 19 million have been infected with the virus. As far as current research has shown, the flu virus appears to be much more infectious than the coronavirus because it is spread through droplets that one can breathe, sneeze or cough out, and can be transferred through fomites. One of the most worrisome facts of the coronavirus in my opinion is its long incubation period in comparison to the flu. This means that people can spread the coronavirus for much longer without knowing they are infected. However, according to a board of director on the American Academy of Family physicians, the fear from the coronavirus comes from the unknown nature of this virus, as opposed to influenza which has been around for years. The flu’s danger comes from secondary infections, which usually emerge when the immune system is compromised or weak (Andrew, 2019). I think that a lot of fear surrounding the coronavirus involves xenophobic attitudes towards china, and an underplay of the real dangers that the flu virus imposes on the United States every year.

Why does the Influenza Vaccine Change every year?

In Microbiology, we are learning about antigenic shift and drift. It’s very interesting because it’s so relevant, especially to influenza viruses. Due to its constantly changing nature, it can be hard for scientists to keep up by producing vaccines that match the current flu viruses. Every year, scientists try to predict as best they can what antigenic properties— or surface proteins — will be targeted by the vaccine that year according to an article by the CDC. Antigenic Drift occurs when genes in a virus mutate, resulting in viruses that are very similar to one another, yet requiring different antibodies to recognize and kill them. Vaccines that are produced to protect people from one virus will often protect people from viruses that are closely related to each other. However, with antigenic drift, the antibodies will not be able to recognize a virus in your system because it is sufficiently different. Antigenic shift is less common, but occurs when an animal-infecting influenza grows HA and NA proteins which can infect humans, and becomes a human virus with no antibodies present in humans (CDC, 2019). I think that antigenic shift is more threatening, due to the fact that no one has antibodies for these types of viruses, yet antigenic drift is more common so we must worry more about this type of mutation.