Learn Hardcore Spanish (Spain): La misma enfermera vacuna a muchos niños para protegerlos. - The same nurse vaccinates many children to protect them.

La misma enfermera means the same nurse – it implies that this nurse has already been mentioned or is being contrasted with other nurses. For example:

Ayer vacunó a mi hijo una enfermera. Hoy la misma enfermera vacuna a muchos niños.
Yesterday a nurse vaccinated my son. Today the same nurse vaccinates many children.

So misma adds the idea of identity: it’s that very nurse again, not a different one.

What exactly does misma mean here, and could I say la enfermera misma instead?

In la misma enfermera, misma means same, and it must go before the noun:

la misma enfermera = the same nurse

If you say la enfermera misma, the meaning changes. It becomes more like the nurse herself, used for emphasis, similar to la propia enfermera:

La enfermera misma prepara las vacunas.
The nurse herself prepares the vaccines.

So:

la misma enfermera → the same nurse (identity)
la enfermera misma → the nurse herself (emphasis)

Why is it enfermera (feminine) and not enfermero?

Spanish marks grammatical gender on nouns:

enfermera = female nurse
enfermero = male nurse

Since the sentence uses la (feminine article) and misma (feminine form), everything agrees:

la misma enfermera (all feminine, singular)

If the nurse were male, you’d say:

El mismo enfermero vacuna a muchos niños para protegerlos.

What verb form is vacuna? Why not vacunar or vacunando?

Vacuna here is:

3rd person singular, present indicative of vacunar
→ (ella) vacuna = she vaccinates / she is vaccinating

Forms:

vacunar = infinitive, to vaccinate
vacunando = gerund, vaccinating
(ella) vacuna = she vaccinates / she is vaccinating

Spanish often uses the simple present for actions that in English can be:

She vaccinates
She is vaccinating

So La misma enfermera vacuna… can correspond to both The same nurse vaccinates… and The same nurse is vaccinating…, depending on context.

Why is there an a in vacuna a muchos niños?

That a is the personal a, used before direct objects that are people (or treated like people).

vacunar a alguien = to vaccinate someone

Because niños are people, Spanish normally uses a:

vacuna a muchos niños = vaccinates many children

Without a, vacuna muchos niños sounds wrong or at least very unnatural in this context to most speakers of Spanish from Spain. For learners, a good rule is:

When a person or people are the direct object, use a (except with tener and some special cases).

Why is it muchos niños and not muchas niños or mucho niños?

Spanish adjectives and quantifiers agree in gender and number with the noun:

niños = masculine plural → needs masculine plural form

So:

mucho niño = much / a lot of boy (singular masculine)
muchos niños = many boys / many children (plural masculine)
mucha niña = much / a lot of girl (singular feminine)
muchas niñas = many girls (plural feminine)

Here:

muchos (masc. plural) agrees with niños (masc. plural).

Why is there no article before muchos niños (why not a los muchos niños)?

Muchos niños is indefinite: many children in general, not specific children already known in the conversation.

If you said a los muchos niños, it would sound like you’re talking about a very specific group of many children that both speakers already have in mind, and it’s quite unusual in this context.

So:

a muchos niños → to many children (general)
a los niños → to the children (specific group)
a los muchos niños → to the many children (a particular, already-known “many”)

What does para add in para protegerlos? Could I use por instead?

Para here expresses purpose or goal:

para protegerlos = in order to protect them, to protect them

In Spanish:

para → purpose / finality (what for? / in order to…)
por → cause, reason, means, duration, etc. (because of, through, by, for [time])

So:

La misma enfermera vacuna a muchos niños para protegerlos.
= The same nurse vaccinates many children in order to protect them.

Using por (por protegerlos) would be incorrect here if you mean purpose. You need para.

Why is it protegerlos and not proteger a ellos?

Protegerlos uses a direct object pronoun:

proteger = to protect
los = them (masculine plural direct object)

Attached to the infinitive:

proteger + los → protegerlos = to protect them

You could say para proteger a los niños instead of para protegerlos, but:

para proteger a ellos is not used in this context; a + pronoun (a ellos) is normally for emphasis or contrast, and you’d still usually also have the pronoun:
- …para protegerlos a ellos. (to protect them, as opposed to others)

So the normal options are:

para protegerlos (most usual, with pronoun)
para proteger a los niños (repeating the noun)

Why los and not les in para protegerlos? I thought people often say les in Spain.

Standard grammar distinguishes:

los / las → direct object pronouns
les → indirect object pronoun

Here, niños are the direct object of proteger:

proteger a los niños → protegerlos

So the “correct” textbook form is protegerlos.

In Spain, there is leísmo: many speakers say le or les as direct objects when referring to people, especially masculine. So you will hear:

para protegerles

in real speech. However, for a learner, it is safer and more universally accepted to use:

para protegerlos for a los niños

Why is los attached to proteger? Could I put it before instead?

With infinitives, gerunds, and affirmative commands, object pronouns are normally attached to the verb:

proteger + los → protegerlos

You also have the option (when there is another conjugated verb before) to place the pronoun before the conjugated verb instead:

La misma enfermera los vacuna para proteger.
(grammatically possible, but odd here because you lose the object for proteger)

In this sentence, the natural pattern is:

vacuna a muchos niños para protegerlos.

If you change the structure so proteger is conjugated, the pronoun moves:

…para que los proteja. = so that she protects them

So:

Infinitive: protegerlos
Conjugated: los protege, que los proteja, etc.

Could this sentence use a reflexive verb like vacunarse instead of vacuna?

Vacunar vs vacunarse:

vacunar (a alguien) = to vaccinate someone
vacunarse = to get oneself vaccinated

In your sentence, the nurse is vaccinating other people:

La misma enfermera vacuna a muchos niños…
→ The nurse is the one who performs the action on them.

If you said:

Muchos niños se vacunan para protegerse.

then:

se vacunan = they get vaccinated (they do it to themselves / have it done for themselves)
protegerse = to protect themselves

So in the original, vacuna (non‑reflexive) is correct because the nurse acts on the children, not on herself.

Can I say La misma enfermera está vacunando a muchos niños para protegerlos? What’s the difference?

Yes, you can say:

La misma enfermera está vacunando a muchos niños para protegerlos.

Difference:

vacuna (simple present) → often used for current actions, habits, or general facts
- She vaccinates many children / She is vaccinating many children.
está vacunando (present progressive) → focuses more clearly on an action in progress right now
- She is in the process of vaccinating many children (right now).

In everyday Spanish (Spain), the simple present (vacuna) is very common even for actions happening around now, so the original sentence is perfectly natural.