The top eight teams in the one-day rankings on September 30, excluding co-hosts South Africa and Zimbabwe, qualify directly for the event.
Afghanistan's win in Belfast on Monday ensured they would finish among those teams, joining Australia, India, New Zealand, Pakistan, Sri Lanka, England and Bangladesh.
The West Indies are ranked 10th and cannot make up enough ground to qualify directly despite having two ODIs against India left to play before the cut-off date.
They also failed to seal an automatic spot at the 2023 edition and lost in the qualifiers, resulting in their absence from a men's 50-over World Cup for the first time.
The Caribbean side successfully negotiated the qualifiers to play at the 2019 edition.
Afghanistan scored a comfortable three-wicket win over Ireland with 4.1 overs remaining, with Rahmanullah Gurbaz's 71 setting them up for their 7-207 total in response to the hosts' 206.
Under the new format for 2027, the winner of the qualifying round will advance directly to the second stage of the World Cup, while the teams placing second, third and fourth will play in the first round known as the Super Series.
The 2027 event will be played in South Africa, Zimbabwe and Namibia.
