Question

which of the following is true about influenza?
a. it can be prevented with an annual flu vaccine.
b. there was an influenza pandemic in 2017.
c. it results in the death of tens of thousands of people each year.
d. it is now under control, accounting for few deaths each year.

Explanation:

• Option a: Annual flu vaccines are effective in preventing influenza for many people, though effectiveness can vary.
• Option b: The major influenza pandemic in recent history was not in 2017 (e.g., 1918, 2009 had significant pandemics; 2017 had no major influenza pandemic).
• Option c: Influenza does result in tens of thousands of deaths annually in many regions (e.g., US CDC reports tens of thousands of flu - related deaths yearly).
• Option d: Influenza is not "under control" with few deaths; it still causes significant mortality yearly.

So, options a and c are true statements about influenza. But if we have to choose among the given options (assuming maybe a single correct or multiple, but let's analyze each):

For option a: Annual flu vaccines are a key preventive measure, so this is true.

For option c: Influenza causes tens of thousands of deaths per year in countries like the US, so this is also true.

If we consider the options as presented, and assuming the question might have multiple correct, but let's check again:

• a: True (vaccines help prevent, though not 100% effective, but annual vaccines are recommended for prevention).
• b: False (no major flu pandemic in 2017).
• c: True (flu - related deaths are in tens of thousands annually in many regions).
• d: False (flu still causes significant deaths).

Answer:

a. It can be prevented with an annual flu vaccine, c. It results in the death of tens of thousands of people each year