Quick questions on Antivirals, antibiotics, resistance and immunisation: HSC Biology Module 7

Antibiotics target structures or processes unique to bacteria, sparing host cells.

Antivirals target viral-specific enzymes and life-cycle steps.

Antibiotics do not work against viruses, fungi, protozoa or prions. Many cause side effects by killing beneficial gut bacteria.

Random mutations in bacterial DNA occasionally produce a resistance gene (e.g. beta-lactamase that degrades penicillin). In an antibiotic-free environment, resistance confers no advantage.

Bacteria reproduce rapidly (every 20 minutes in good conditions) and share genes by horizontal gene transfer.

Resistant infections cost lives and treatment dollars. Methicillin-resistant Staphylococcus aureus (MRSA), multi-drug resistant tuberculosis (MDR-TB) and carbapenem-resistant Enterobacteriaceae are major threats. The WHO ranks antibiotic resistance among the top ten threats to global health.

The proportion of the population that must be immune is approximately 1 - 1/R0.

Vaccine hesitancy or supply gaps can drop coverage below the herd immunity threshold. Measles outbreaks resurged in 2019 in parts of Europe, North America and the Pacific where coverage had fallen.

Quote the formula $1 - \tfrac{1}{R_0}$, substitute the R0, and if a vaccine efficacy is given, divide the threshold by efficacy to get required coverage. State both numbers.

"Outline" = brief points; "describe" = ordered steps; "compare" = same features for each tool; "assess/evaluate" = a justified judgement weighing effectiveness against limitations, with evidence.