Katten kan kräkas efter vaccinet.

Because katten is the definite form, meaning the cat.

In Swedish, nouns often add an ending to show definiteness:

• en katt = a cat
• katten = the cat

So Katten kan kräkas efter vaccinet is talking about a specific cat, not cats in general.

For the same reason: vaccinet is the definite form of vaccin, so it means the vaccine.

Vaccin is a neuter noun (an ett-word):

• ett vaccin = a vaccine
• vaccinet = the vaccine

The definite ending for many ett-words is -et.

Kan is the present tense of kunna, which usually means can / be able to.

In this sentence, kan expresses possibility, so it is often understood like:

• can
• may
• sometimes might

So it does not necessarily mean the cat definitely will vomit, only that it is possible.

After modal verbs like kan, Swedish uses the infinitive without att.

So:

• kan kräkas = can vomit

This is similar to English, where we say can vomit, not can to vomit.

Compare:

• Katten kan kräkas. = The cat can vomit.
• Katten vill sova. = The cat wants to sleep.

So kräkas stays in the infinitive form because it follows the modal verb kan.

It looks a bit like a reflexive or passive form, but here kräkas is just the normal dictionary form of the verb meaning to vomit.

This type of verb can be confusing because -s endings in Swedish are used in several ways. In this case, you should learn kräkas as a complete verb.

A few useful forms are:

• infinitive: kräkas
• present: kräks
• past: kräktes
• supine: kräkts

So yes, the form may look unusual, but it is normal Swedish.

Efter means after, so efter vaccinet means after the vaccine.

In natural English, this often means:

• after receiving the vaccine
• after the vaccination
• after being vaccinated

In Swedish, this shorter phrasing is very common.

This is the normal word order for a main clause in Swedish:

• subject: Katten
• finite verb: kan
• infinitive/main verb: kräkas
• time expression/prepositional phrase: efter vaccinet

So the sentence follows a basic pattern: Subject + finite verb + infinitive + other information

Swedish main clauses also follow the V2 rule, which means the finite verb usually comes in the second position.

For example, you could also say:

• Efter vaccinet kan katten kräkas.

That is still correct, because kan remains the second element.

Yes, that is often the practical meaning, but the Swedish wording is slightly more literal: after the vaccine.

The sentence focuses on timing first: vomiting happens after the vaccine. In context, people will usually understand that this is a possible side effect.

If you wanted to emphasize cause more directly, Swedish might use a different phrasing, for example with av in some contexts, but efter vaccinet is very natural when talking about symptoms following treatment.

As written, it refers to one specific cat, because of katten = the cat.

If you wanted to talk about cats in general, Swedish would usually say:

• Katter kan kräkas efter vaccin.
• En katt kan kräkas efter ett vaccin.

The exact wording would depend on the situation, but katten clearly points to a particular cat.

A common past-tense version would be:

• Katten kunde kräkas efter vaccinet.

Here, kunde is the past tense of kan/kunna.

Depending on context, that can mean:

• The cat could vomit after the vaccine
• The cat was able to vomit after the vaccine
• sometimes The cat might vomit after the vaccine, in a past-context sense

If you want to say the cat actually did vomit, Swedish would more naturally say something like:

• Katten kräktes efter vaccinet.

That means the vomiting really happened.