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RNA viruses possess polymerases that lack or have poor proofreading ability, whereas many DNA viruses rely on host polymerases for genome synthesis. Compared to these DNA viruses, RNA viruses would have ______.

With the spread of antibiotic resistance, e.g. MDR-TB or MRSA, we are having to move from drugs with a ______ therapeutic index like penicillin and instead use those with a ______ therapeutic index which have greater harmful side effects.

Genetic recombination in segmented viruses such as influenza can lead to new, potentially dangerous viruses because ______.

Each year, researchers track strains of influenza as they develop an updated influenza vaccine. In recent years, this vaccine has been a quadrivalent one, i.e., one containing antigens targeting four influenza strains (two type A and two type B influenza viruses), although for the 2024-2025 season, the influenza B/Yamagata strain has been dropped from the vaccine (this is because we have not detected it since March 2020, and we believe we have driven it to extinction as a result of non-pharmaceutical interventions implemented at the start of the COVID pandemic – i.e., a happy victory for humans!) In addition to the possibility of changing strains based on their prevalence, researchers update the specific antigens for each strain involved. This is because even if a strain included last year is still a dominant one this year, it will have undergone sufficient ______ via the accumulation of point mutations that the effectiveness of our immune response from last year will not be as protective this year.

Optional up to 2 points of extra credit: Shown is the cumulative risk and burden of sequelae in populations infected one or more times with SARS-CoV-2 compared with uninfected controls from a study of 5,819,264 people (Acute and postacute sequelae associated with SARS-CoV-2 reinfection, Bowe, Xie & Ziyad Al-Aly, Nature Medicine volume 28, pages 2398–2405 (2022)). Data for multiple outcomes is visualized as the hazard ratio (HR) and excess burden per 1,000 persons for one, two, and three or more infections compared to uninfected controls. Outcomes (starting from top left and ranging to bottom left) include hospitalization, at least one sequela, cardiovascular, coagulation and hematological, diabetes, fatigue, gastrointestinal, kidney, mental health, musculoskeletal, neurological, and pulmonary. Figure 1. Cumulative risk and burden of sequelae in people with one (green), two (red), and three or more (purple) SARS-CoV-2 infections compared to noninfected controls. 1. What does this data suggest repeat infections by SARS-CoV-2 are doing to the population studied? Please explain. Include information and descriptions from the graph to support your explanation. 2. Propose an explanation as to what the virus might be doing to result in this trend. 3. Comment briefly on the sample size of this study – should this sample size give us confidence in this work? Why or why not? 4. Considering the excess burden bar graphs to the right, what might be the impact of this information on the healthcare system in the U.S.?

Which coronary artery is most commonly associated with an anterior myocardial infarction?

A key ECG feature of RBBB is:

Failure to sense occurs when:

Which test is best suited for evaluating orthostatic hypotension?

Occlusion of which artery would cause ST elevation in leads II, III, and aVF?