Defence against disease Flashcards
(180 cards)
1
Q
What is a pathogen?
A
A pathogen is a disease-causing organism that can infect humans and other organisms.
2
Q
What are the main types of pathogens?
A
The main types of pathogens are viruses, bacteria, fungi, and protists.
3
Q
Are archaea known to cause diseases in humans?
A
No, archaea are not known to cause any diseases in humans.
4
Q
What are some examples of bacterial pathogens?
A
Examples include Streptococcus pneumoniae, Staphylococcus aureus, Escherichia coli (E. coli), and Klebsiella pneumoniae.
5
Q
What types of diseases can viruses cause?
A
Viruses can cause a wide range of diseases, from the common cold to AIDs.
6
Q
What are some examples of diseases caused by fungi?
A
Fungi can cause skin diseases like ringworm and athlete’s foot, as well as infections in the lungs or nervous system.
7
Q
What is an example of a disease caused by a protist?
A
Malaria is caused by a protist parasite called Plasmodium.
8
Q
What was the significance of Ignaz Semmelweis’s observations in Vienna during the 1840s?
A
Semmelweis observed higher mortality rates in maternity wards attended by medical students compared to midwives, leading to the introduction of hand washing with chlorinated lime solution, which dramatically reduced mortality rates.
9
Q
What important discovery did John Snow make during the 1854 cholera epidemic in London?
A
John Snow mapped cholera cases in London, identifying a contaminated water pump as the source, which led to the understanding of cholera as a waterborne disease and improvements in urban sanitation.
10
Q
How did the observations of Semmelweis and Snow contribute to the field of infectious diseases?
A
These observations were crucial in developing germ theory and improving public health measures to control infectious diseases.
11
Q
What is the primary function of the skin as a barrier?
A
The skin acts as both a physical and chemical barrier to protect against pathogens.
12
Q
How does the skin serve as a physical barrier?
A
The skin provides a continuous, impassable barrier that prevents the entry of potentially infectious pathogens.
13
Q
What role does desquamation play in skin defense?
A
Desquamation, or the shedding of dead skin cells, helps dislodge pathogens that may have adhered to the skin surface.
14
Q
How does the skin’s acidity contribute to pathogen defense?
A
The skin’s acidity creates an unfavorable environment for many pathogens, helping to kill or inactivate them.
15
Q
What is the role of beneficial microorganisms on the skin?
A
Beneficial microorganisms compete with invading pathogens, preventing their colonization and reducing the risk of infection.
16
Q
What are antimicrobial peptides (AMPs)?
A
AMPs are small peptides secreted by skin cells that have antibiotic-like properties, directly killing pathogens and enhancing immune responses.
17
Q
How do keratinocytes contribute to skin immunity?
A
Keratinocytes act as active immune cells that release inflammatory cytokines and antimicrobial molecules in response to pathogens.
18
Q
What is the function of mucous membranes in pathogen defense?
A
Mucous membranes line body cavities and secrete mucus, which traps pathogens and facilitates their removal from the body.
19
Q
How do tears contribute to eye health?
A
Tears contain enzymes that act as chemical barriers, helping to wash away pathogens and prevent infections in the eyes.
20
Q
What happens when the skin barrier is breached?
A
When the skin barrier is compromised, it allows pathogens to enter, leading to potential infections; this activates the innate immune system for protection.
21
Q
What is the primary purpose of blood clotting?
A
The primary purpose of blood clotting is to seal cuts in the skin, preventing blood loss and pathogen entry.
22
Q
What initiates the blood clotting process?
A
The process is initiated when platelets adhere to the site of a cut or injury.
23
Q
What do platelets release during the clotting process?
A
Platelets release clotting factors that trigger a cascade of reactions leading to blood clot formation.
24
Q
What is the coagulation cascade?
A
The coagulation cascade is a series of complex biochemical reactions that lead to the formation of a blood clot.
25
What enzyme is activated during the coagulation cascade?
The enzyme thrombin is activated during the coagulation cascade.
26
What is the role of thrombin in blood clotting?
Thrombin catalyzes the conversion of fibrinogen, a soluble plasma protein, into fibrin, which is insoluble.
27
How does fibrin contribute to clot formation?
Fibrin strands form a mesh that traps platelets and erythrocytes (red blood cells), stabilizing the clot at the injury site.
28
What happens to erythrocytes during clot formation?
Erythrocytes are trapped within the fibrin mesh, contributing to the overall structure and stability of the clot.
29
What is the significance of rapid conversion of fibrinogen to fibrin?
The rapid conversion ensures that bleeding is quickly controlled and that a stable barrier is formed to protect against infection.
30
How does the body eventually remove a blood clot once healing occurs?
Once healing is complete, an enzyme called plasmin is activated to dissolve the clot in a process known as fibrinolysis.
31
What is the primary characteristic of the innate immune system?
The innate immune system responds to broad categories of pathogens and provides an immediate, non-specific defense.
32
How does the adaptive immune system differ from the innate immune system?
The adaptive immune system responds in a specific way to particular pathogens and develops memory for previously encountered pathogens.
33
Does the innate immune system change throughout an organism's life?
No, the innate immune system does not change during an organism’s life; it remains constant.
34
What is the response time of the innate immune system?
The innate immune system responds rapidly, typically within minutes to hours after exposure to pathogens.
35
What is the response time of the adaptive immune system?
The adaptive immune system has a slower response time, taking days or even weeks to develop on first encounter with a pathogen.
36
What role do phagocytes play in the innate immune system?
Phagocytes are key components of the innate immune system that engulf and destroy pathogens.
37
How does the adaptive immune system build memory?
The adaptive immune system builds memory by creating long-lived memory cells that remember specific pathogens for faster responses upon re-exposure.
38
What type of immunity does the adaptive immune system provide?
The adaptive immune system provides specific immunity against particular pathogens, allowing for a targeted response.
39
Can the adaptive immune system be enhanced through vaccination?
Yes, vaccination stimulates the adaptive immune system to recognize and remember specific pathogens without causing disease.
40
Why is it important for both the innate and adaptive immune systems to work together?
The collaboration between both systems ensures a comprehensive defense against infections, with the innate system providing immediate protection while the adaptive system develops long-term immunity.
41
What is the primary function of phagocytes in the immune system?
Phagocytes are responsible for engulfing and digesting pathogens to help control infections.
42
How do phagocytes move to sites of infection?
Phagocytes use amoeboid movement to migrate from the blood to sites of infection.
43
What is amoeboid movement?
Amoeboid movement is a crawling-like motion where phagocytes change shape by extending parts of their cell membrane to form pseudopodia.
44
How do phagocytes recognize pathogens?
Phagocytes recognize pathogens through specific receptors that bind to pathogen-associated molecular patterns (PAMPs).
45
What process do phagocytes use to engulf pathogens?
Phagocytes engulf pathogens through a process called endocytosis, forming a vesicle known as a phagosome.
46
What happens to the phagosome after engulfing a pathogen?
The phagosome matures into a phagolysosome, where it fuses with lysosomes that contain digestive enzymes.
47
What role do lysosomal enzymes play in pathogen destruction?
Lysosomal enzymes digest the engulfed pathogens, breaking them down into smaller components.
48
How do reactive oxygen species (ROS) contribute to pathogen killing?
Reactive oxygen species generated in the phagolysosome help kill pathogens through oxidative damage.
49
What is the significance of phagocytosis in the immune response?
Phagocytosis is crucial for eliminating invading pathogens and maintaining homeostasis by clearing dead cells and debris.
50
How do phagocytes communicate with other immune cells during an infection?
Phagocytes produce cytokines that recruit other immune cells to the site of infection, enhancing the overall immune response.
51
What are lymphocytes?
Lymphocytes are a type of white blood cell that plays a crucial role in the adaptive immune system.
52
What are the two main types of lymphocytes involved in the adaptive immune response?
The two main types are B lymphocytes (B cells) and T lymphocytes (T cells).
53
Where do lymphocytes circulate in the body?
Lymphocytes circulate in the blood and are also contained in lymph nodes.
54
What is the primary function of B lymphocytes?
B lymphocytes are responsible for producing antibodies specific to particular antigens.
55
How many different types of B lymphocytes does an individual typically have?
An individual has a very large number of B lymphocytes, each producing a specific type of antibody.
56
What happens when a B cell encounters its specific antigen?
Upon encountering its specific antigen, a B cell becomes activated, proliferates, and differentiates into plasma cells and memory B cells.
57
What do plasma cells do?
Plasma cells are specialized B cells that secrete large quantities of antibodies into the bloodstream.
58
What is the role of memory B cells?
Memory B cells provide long-lasting immunity by remaining in the body and responding more rapidly upon re-exposure to the same pathogen.
59
How do antibodies function in the immune response?
Antibodies bind to specific antigens on pathogens, neutralizing them or marking them for destruction by other immune cells.
60
How do T lymphocytes assist B lymphocytes in producing antibodies?
Helper T cells provide signals and cytokines that activate B cells, enhancing their ability to produce antibodies effectively.
61
What is an antigen?
An antigen is a molecule that can trigger an immune response, specifically activating lymphocytes to produce antibodies.
62
What types of molecules are most antigens typically composed of?
Most antigens are glycoproteins or other proteins located on the outer surfaces of pathogens.
63
How do antigens function in the immune system?
Antigens serve as recognition molecules that help the immune system identify foreign substances, prompting an immune response.
64
Where are antigens commonly found?
Antigens are usually found on the surfaces of viruses, bacteria, fungi, and other pathogens, as well as on the surface of cells.
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What happens when an antigen is recognized by the immune system?
When recognized, the immune system activates specific lymphocytes (B cells and T cells) to respond to the pathogen.
66
What role do antibodies play in response to antigens?
Antibodies bind to specific antigens, neutralizing pathogens or marking them for destruction by other immune cells.
67
How do blood group antigens relate to transfusions?
Antigens on the surface of erythrocytes (red blood cells) can stimulate antibody production if transfused into a person with a different blood group, leading to potential transfusion reactions.
68
What is the significance of glycosylation in antigens?
Glycosylation can influence the antigenic properties of proteins, affecting how they are recognized by the immune system.
69
What are epitopes?
Epitopes are specific regions or fragments of an antigen that are recognized by antibodies or T-cell receptors.
70
Why is it important for the immune system to distinguish between self and non-self antigens?
The ability to distinguish self from non-self helps prevent autoimmune reactions, where the immune system mistakenly attacks the body's own tissues.
71
What is the role of B-lymphocytes in the immune system?
B-lymphocytes (B cells) produce antibodies and can become memory cells upon activation.
72
How are B cells activated?
B cells are activated when they encounter their specific antigen and receive signals from helper T-lymphocytes that have also been activated by the same antigen.
73
What is required for B cell activation?
Activation requires both direct interaction with the specific antigen and contact with an activated helper T cell.
74
What is the function of helper T-lymphocytes in the activation of B cells?
Helper T cells provide necessary signals, including cytokines, that stimulate B cells to proliferate and differentiate into antibody-secreting plasma cells.
75
Where does B cell activation primarily occur?
B cell activation primarily occurs in secondary lymphoid organs, such as lymph nodes and the spleen.
76
What is the significance of antigen-specific interactions between B cells and helper T cells?
Antigen-specific interactions ensure that only B cells that recognize the same pathogen as the activated T cell will be stimulated to produce antibodies.
77
What happens to a B cell after it is activated?
After activation, a B cell proliferates and differentiates into plasma cells that secrete antibodies or memory B cells that provide long-term immunity.
78
How do B cells internalize antigens for processing?
B cells internalize antigens through receptor-mediated endocytosis, where the antigen binds to the B cell receptor (BCR).
79
What role do cytokines play in B cell activation?
Cytokines released by helper T cells enhance B cell activation, proliferation, and differentiation into plasma cells.
80
Why is it important for the immune response to have both specific and helper interactions?
Specific interactions ensure targeted responses to pathogens, while helper interactions enhance the overall effectiveness of the immune response by coordinating various immune functions.
81
What happens to B-lymphocytes when they are activated by an antigen?
Activated B-lymphocytes undergo mitosis to multiply and produce large numbers of plasma cells.
82
What is the primary function of plasma cells?
Plasma cells are specialized B cells that secrete antibodies specific to the encountered antigen.
83
Why are there initially relatively small numbers of B-cells that respond to a specific antigen?
The immune system has a diverse repertoire of B-cells, but only a few are specific to any given antigen until activated.
84
How do activated B-cells produce sufficient quantities of antibodies?
Activated B-cells divide by mitosis to form clones, resulting in a large population of plasma B-cells capable of producing the same type of antibody.
85
What is the process by which B-lymphocytes multiply after activation called?
The process is called clonal expansion.
86
How many antibodies can a single plasma cell secrete per second?
A single plasma cell can secrete several thousand antibodies per second.
87
What is the significance of clonal expansion in the immune response?
Clonal expansion ensures that there are enough antibody-secreting cells to effectively combat an infection.
88
What occurs during the differentiation of activated B-cells into plasma cells?
Activated B-cells differentiate into plasma cells that produce and secrete large amounts of antibodies tailored to the specific antigen.
89
How long do plasma cells typically live after activation?
Plasma cells can live for several days to months, continuously producing antibodies during that time.
90
What role do memory B-cells play in the immune system?
Memory B-cells persist long-term and provide rapid responses upon re-exposure to the same antigen, enhancing the effectiveness of the immune response.
91
What is immunity?
Immunity is the ability to eliminate an infectious disease from the body, providing protection against pathogens.
92
What are memory cells?
Memory cells are long-lived lymphocytes that retain the ability to produce specific antibodies needed to fight infections.
93
How do memory cells contribute to the immune response?
Memory cells enable a faster and more effective immune response upon re-exposure to the same pathogen.
94
What types of lymphocytes can become memory cells?
Both B lymphocytes (B cells) and T lymphocytes (T cells) can differentiate into memory cells after an immune response.
95
How do memory B cells function in subsequent infections?
Upon re-encountering their specific antigen, memory B cells rapidly proliferate and differentiate into plasma cells that produce antibodies.
96
What is the significance of long-term survival of memory cells?
Long-term survival of memory cells ensures that the immune system can quickly respond to previously encountered pathogens, reducing the severity of infections.
97
How does the presence of memory T cells enhance immune protection?
Memory T cells can quickly activate and proliferate upon re-exposure to their specific antigen, coordinating a robust immune response.
98
What role do vaccines play in developing immunity?
Vaccines stimulate the production of memory cells without causing disease, preparing the immune system for future encounters with pathogens.
99
How does clonal expansion relate to memory cell formation?
During an initial immune response, activated B and T cells undergo clonal expansion, resulting in a population of memory cells that persist long-term.
100
Why are booster shots important for maintaining immunity?
Booster shots help reinforce the immune response by stimulating the production of additional memory cells, ensuring continued protection against specific diseases.
101
What is HIV?
HIV (Human Immunodeficiency Virus) is a virus that attacks the immune system, specifically targeting CD4+ T lymphocytes.
102
Through which body fluids can HIV be transmitted?
HIV can be transmitted through blood, semen, vaginal fluids, rectal fluids, pre-seminal fluid, and breast milk.
103
What must occur for HIV transmission to take place?
For transmission to occur, HIV must come into contact with a mucous membrane or damaged tissue, or be directly injected into the bloodstream.
104
What are mucous membranes?
Mucous membranes are found in areas such as the rectum, vagina, penis, and mouth; they are susceptible to HIV infection.
105
How is sexual contact a major route of HIV transmission?
Sexual intercourse allows direct contact with infected bodily fluids, facilitating the entry of HIV through mucous membranes.
106
Can HIV be transmitted through sharing needles?
Yes, sharing needles or syringes with an infected person is a common route for HIV transmission.
107
What is perinatal transmission of HIV?
Perinatal transmission refers to the transfer of HIV from an infected mother to her child during pregnancy, childbirth, or breastfeeding.
108
Are there any body fluids that do not transmit HIV?
Yes, saliva, tears, urine, and feces are not considered infectious for HIV transmission.
109
How does the risk of transmission vary with viral load?
Individuals with a detectable viral load are more likely to transmit HIV; effective antiretroviral therapy (ART) can reduce viral load to undetectable levels, significantly lowering transmission risk.
110
What precautions can be taken to prevent HIV transmission?
Using condoms during sexual activity, not sharing needles, and ensuring that pregnant women receive appropriate medical care can help prevent the transmission of HIV.
111
What type of lymphocyte does HIV primarily infect?
HIV primarily infects CD4+ T lymphocytes, also known as helper T cells.
112
How does HIV lead to the depletion of CD4+ T cells?
HIV binds to CD4 receptors on T cells, enters the cells, replicates, and ultimately causes cell death, leading to a reduction in CD4+ T cell numbers.
113
What is the consequence of reduced CD4+ T cell counts in the body?
A reduction in CD4+ T cells limits the immune system's ability to produce antibodies and fight off infections
114
What is AIDS?
AIDS (Acquired Immunodeficiency Syndrome) is the most severe stage of HIV infection, characterized by a significantly weakened immune system and the presence of opportunistic infections or certain cancers.
115
How does the immune system's response change as HIV progresses to AIDS?
As HIV progresses, the immune system becomes increasingly compromised, leading to difficulty in responding to infections and a higher risk of opportunistic infections.
116
What are opportunistic infections (OIs)?
Opportunistic infections are infections that occur more frequently and are more severe in individuals with weakened immune systems, such as those with HIV/AIDS.
117
At what CD4+ T cell count is a person typically diagnosed with AIDS?
A person is diagnosed with AIDS when their CD4+ T cell count falls below 200 cells/mm³, regardless of the presence of opportunistic infections.
118
How does HIV affect the body's ability to respond to common infections?
HIV weakens the immune response, making it harder for the body to fight off common infections, leading to prolonged and more severe illnesses.
119
What role do antiretroviral therapies (ART) play in managing HIV infection?
Antiretroviral therapies help suppress viral replication, increase CD4+ T cell counts, and improve overall immune function, reducing the risk of progression to AIDS.
120
Why is early detection and treatment of HIV crucial?
Early detection and treatment can prevent significant immune system damage, reduce the risk of opportunistic infections, and improve long-term health outcomes for individuals living with HIV.
121
What are antibiotics?
Antibiotics are chemicals that inhibit the growth of or kill bacteria by targeting specific bacterial processes.
122
How do antibiotics selectively target bacteria?
Antibiotics target processes unique to bacteria, such as cell wall synthesis, protein synthesis, and nucleic acid synthesis, which do not occur in eukaryotic cells.
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What is one common mechanism of action for antibiotics?
One common mechanism is the inhibition of cell wall synthesis, which disrupts the structural integrity of bacterial cells.
124
Can you name a class of antibiotics that inhibits cell wall synthesis?
Beta-lactam antibiotics, such as penicillins and cephalosporins, inhibit cell wall synthesis by targeting penicillin-binding proteins (PBPs).
125
How do antibiotics affect protein synthesis in bacteria?
Antibiotics can inhibit protein synthesis by targeting the bacterial ribosome (30S or 50S subunits), disrupting the translation process.
126
What role does folic acid metabolism play in bacterial infections?
Some antibiotics inhibit folic acid synthesis, which is essential for nucleic acid and amino acid production in bacteria but not in eukaryotic cells.
127
Why do antibiotics fail to control viral infections?
Antibiotics are ineffective against viruses because viruses lack the cellular structures and processes (like cell walls and ribosomes) that antibiotics target.
128
What is a significant reason for antibiotic resistance?
Bacteria can develop resistance through various mechanisms, including altering their target sites, producing enzymes that degrade antibiotics, or employing efflux pumps to expel antibiotics.
129
How does bacterial cell wall composition contribute to antibiotic effectiveness?
The presence of a peptidoglycan layer in bacterial cell walls makes them susceptible to antibiotics that disrupt this structure, while eukaryotic cells lack such walls.
130
What is an example of an antibiotic that disrupts membrane function?
Polymyxin B is an example of an antibiotic that disrupts bacterial cell membrane function, leading to increased permeability and cell death.
131
What is antibiotic resistance?
Antibiotic resistance occurs when bacteria evolve to survive exposure to antibiotics that would normally kill them or inhibit their growth.
132
How do bacteria develop resistance to antibiotics?
Bacteria can develop resistance through genetic mutations, horizontal gene transfer, and natural selection, allowing them to survive in the presence of antibiotics.
133
What are multidrug-resistant (MDR) bacteria?
MDR bacteria are strains of bacteria that are resistant to three or more classes of antimicrobial drugs, posing significant public health risks.
134
Why is careful use of antibiotics necessary?
Careful use of antibiotics helps slow the emergence and spread of multidrug-resistant bacteria, preserving the effectiveness of existing antibiotics.
135
What role does horizontal gene transfer play in antibiotic resistance?
Horizontal gene transfer allows resistant bacteria to share genetic material encoding resistance traits with other bacteria, facilitating the rapid spread of resistance.
136
Can you name some common multidrug-resistant pathogens?
Common multidrug-resistant pathogens include Methicillin-resistant Staphylococcus aureus (MRSA), Carbapenem-resistant Enterobacteriaceae (CRE), and multi-drug resistant Mycobacterium tuberculosis (MDR-TB).
137
What is the impact of overusing antibiotics in healthcare?
Overuse and misuse of antibiotics contribute to the rapid evolution of antibiotic resistance, outpacing the development of new antibiotics.
138
How can new techniques aid in antibiotic discovery?
Techniques such as searching chemical libraries and new bacterial isolation methods can lead to the discovery of novel antibiotics effective against resistant strains.
139
What is one promising new antibiotic discovered through innovative methods?
Teixobactin is a promising new antibiotic discovered from soil bacteria that targets Gram-positive bacteria by interfering with cell wall assembly.
140
Why is it important to continue researching new antibiotics?
Ongoing research is crucial to combat the growing threat of antibiotic-resistant infections and ensure effective treatment options remain available for future generations.
141
What are zoonoses?
Zoonoses are infectious diseases that can be transmitted from non-human animals to humans.
142
What types of pathogens can cause zoonotic diseases?
Zoonotic diseases can be caused by bacteria, viruses, parasites, and fungi.
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How prevalent are zoonoses in humans?
Zoonotic diseases represent a significant public health concern globally, with many infectious diseases in humans having animal origins.
144
What is one example of a bacterial zoonosis?
Bovine tuberculosis is an example of a bacterial zoonosis that can be transmitted from cattle to humans.
145
What is rabies, and how is it transmitted?
Rabies is a viral zoonosis primarily transmitted through the bite of an infected animal, often bats or dogs.
146
What is Japanese encephalitis, and how does it spread?
Japanese encephalitis is a viral infection transmitted by mosquitoes, often associated with pigs and wading birds as amplifying hosts.
147
How did COVID-19 emerge as a zoonotic disease?
COVID-19, caused by the SARS-CoV-2 virus, is believed to have originated from bats and possibly involved an intermediate host before transmitting to humans.
148
What evidence supports the zoonotic origins of COVID-19?
The initial outbreak was linked to the Huanan Seafood Wholesale Market in Wuhan, China, where various animal species were sold.
149
Why are zoonotic diseases a major public health concern?
Zoonotic diseases can lead to widespread outbreaks and have significant impacts on human health, agriculture, and economies.
150
How can zoonoses be prevented?
Preventive measures include proper hygiene practices, vaccination of pets and livestock, controlling vector populations (like mosquitoes), and monitoring wildlife for emerging diseases.
151
What are vaccines?
Vaccines are biological products that stimulate the immune system to develop immunity against specific pathogens without causing the disease.
152
What do vaccines contain?
Vaccines contain antigens or nucleic acids (DNA or RNA) that code for antigens, which trigger an immune response.
153
How do vaccines work to provide immunity?
Vaccines introduce antigens into the body, prompting the immune system to recognize them as foreign and produce specific antibodies.
154
What is the role of antigens in vaccines?
Antigens are components that mimic the appearance or behavior of pathogens, allowing the immune system to prepare defenses against future infections.
155
What are nucleic acid vaccines?
Nucleic acid vaccines use genetic material (DNA or RNA) from a pathogen to instruct host cells to produce antigens, stimulating an immune response.
156
How do DNA vaccines function?
DNA vaccines introduce plasmids containing DNA sequences that encode for specific antigens, which are then expressed by host cells to elicit an immune response.
157
How do RNA vaccines work?
RNA vaccines, such as mRNA vaccines, deliver messenger RNA that instructs cells to produce antigens, triggering an immune response without using live pathogens.
158
Why are nucleic acid vaccines considered advantageous?
Nucleic acid vaccines are relatively easy and quick to produce, can be tailored for different pathogens, and do not require live viruses or bacteria.
159
What is the significance of developing new vaccine technologies?
New vaccine technologies, such as nucleic acid vaccines, enhance the ability to respond rapidly to emerging infectious diseases and improve vaccine efficacy.
160
What is the ultimate goal of vaccination?
The ultimate goal of vaccination is to establish long-term immunity, allowing the immune system to respond quickly and effectively upon re-exposure to the pathogen.
161
What is herd immunity?
Herd immunity is a form of indirect protection that occurs when a sufficient percentage of a population becomes immune to an infectious disease, making it difficult for the disease to spread.
162
How does herd immunity protect individuals who are not immune?
When a large portion of the population is immune, the overall transmission of the disease is reduced, providing protection to those who cannot be vaccinated or are otherwise susceptible.
163
What percentage of a population typically needs to be immune to achieve herd immunity for highly contagious diseases like measles?
For highly contagious diseases like measles, approximately 95% of the population needs to be immune to achieve herd immunity.
164
What are the two main ways individuals can gain immunity?
Individuals can gain immunity either through vaccination or by recovering from an infection.
165
Why is vaccination considered the best way to achieve herd immunity?
Vaccination provides immunity without causing illness, reducing the risk of severe disease and complications that can arise from natural infections.
166
What happens when vaccination rates decline in a community?
Declining vaccination rates can lead to outbreaks of vaccine-preventable diseases, as fewer individuals are protected and the disease can spread more easily.
167
How do vaccines contribute to building herd immunity?
Vaccines stimulate the immune system to produce antibodies, leading to widespread immunity that limits disease transmission within the community.
168
What is the herd immunity threshold (HIT)?
The herd immunity threshold is the critical proportion of a population that must be immune for herd immunity to effectively prevent disease spread.
169
Why is it important for scientists to publish their research on vaccines and herd immunity?
Publishing research allows for peer evaluation and dissemination of knowledge, which can inform public health policies and vaccination strategies.
170
What should consumers be aware of regarding vaccine research and media reporting?
Consumers should recognize that while vaccines undergo rigorous testing, risks of side effects exist, and media reports may circulate before thorough evaluations are completed. Understanding the distinction between pragmatic truths and absolute certainty is essential.
171
What is the purpose of evaluating COVID-19 data?
Evaluating COVID-19 data helps assess the reliability of information regarding case counts, death rates, and the effectiveness of public health interventions.
172
What are some common sources of COVID-19 data?
Common sources include state and local health departments, news reports, and data aggregators like Johns Hopkins University and The COVID Tracking Project.
173
What is the case fatality rate (CFR)?
The case fatality rate (CFR) is a measure used to assess the severity of an infectious disease, calculated as the number of deaths divided by the number of confirmed cases.
174
Why is it important to use multiple data sources for COVID-19 evaluation?
Using multiple data sources helps provide a more comprehensive view of the pandemic and accounts for discrepancies due to reporting delays or variations in data collection methods.
175
What statistical method was used to assess inter-rater reliability (IRR) among COVID-19 data aggregators?
A Kappa variant called linearly weighted Cohen’s Kappa (LWCK) was used to evaluate agreement between paired aggregators.
176
How can percentage change be calculated?
Percentage change is calculated using the formula:
New Value - Old Value / Old Value x 100%
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What is an example of calculating percentage change?
If cases increased from 200 to 240, the percentage change would be:
240 - 200 / 200 x 100% = 20%
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How is percentage difference calculated?
Percentage difference is calculated using the formula:
value 1 - value 2 / (value 1 + value / 2) x 100%
179
What is an example of calculating percentage difference?
For values 200 and 240, the percentage difference would be:
240 - 200 / (200 + 240 / 2) x 100% = 18.18%
180
Why is it important for scientists to publish their research on COVID-19?
Publishing research allows for peer evaluation, transparency, and dissemination of findings that can inform public health policies and responses to the pandemic.
