Learn Hardcore Spanish (Latin America): La segunda vacuna se aplica después de un mes para mayor protección. - The second vaccine is applied after one month for greater protection.

The se in se aplica is the “passive/impersonal se.” It turns the verb into a passive construction meaning “is administered” without saying who does it. In English you’d say “The second vaccine is administered…”—in Spanish that role is played by se aplica.

Why do we say la segunda vacuna? How does gender and word order work with vacuna and segunda?

• Vacuna is a feminine noun, so it takes the feminine article la.
• Ordinal numbers (primero, segundo, tercera, etc.) agree in gender and number with the noun they modify, so we say segunda vacuna (not segundo vacuna).
• In Spanish, ordinals almost always come before the noun.

Why is it después de un mes and not después un mes? What is the role of de here?

The phrase después de is a fixed preposition that requires de before any noun or time expression. You need de to link después with un mes. Without it, the phrase would be grammatically incorrect.

Could we say un mes después instead of después de un mes? Does it change the meaning or formality?

Yes, un mes después is grammatically correct and means the same thing (“one month later”). It’s slightly more informal in writing and often used in narratives or spoken Spanish, but the meaning doesn’t change.

What does para mayor protección mean, and why use para?

• Para introduces purpose: “in order to” or “for the purpose of.”
• Para mayor protección literally means “for greater protection.” It tells us the reason why the second vaccine is given after a month.

Why mayor protección instead of mejor protección? What’s the difference between mayor and mejor?

• Mayor is the comparative of grande and conveys “greater” in quantity or degree (more protection).
• Mejor is the comparative of bueno and conveys “better” in quality.
Here you want to emphasize “more protection,” not “a better kind of protection,” so mayor protección is the right choice.

Can I add una before mayor protección, or include a verb like obtener or tener (e.g., para una mayor protección or para obtener mayor protección)? Is it correct?

Yes, you can say para una mayor protección—the article una is optional and adds a slight emphasis. You can also say para obtener mayor protección or para tener mayor protección. In everyday Spanish, speakers often omit obtener/tener because it’s understood.

Could we use a different verb like ponerse instead of aplicarse, e.g., La segunda vacuna se pone después de un mes? When do we use aplicar vs poner for vaccines?

• Aplicar (or administrar) is the formal/medical term meaning “to administer” a vaccine.
• Ponerse (reflexive of poner) is common in colloquial speech: ponerse la vacuna means “to get vaccinated” (focus on the person receiving it).
Both are correct; the original sentence uses the more clinical se aplica, but you’ll hear “la segunda vacuna te la pones después de un mes” in everyday conversation.