Luke Romano is the fourth All Black in the past month to catch the mumps.
The Crusaders lock has been quarantined to join Jack Goodhue, Rieko Ioane and Ardie Savea as other All Blacks to suffer from the contagious virus on this northern tour.
All Blacks coach Steve Hansen revealedafter his side's 33-18 win over Wales in Cardiff, their final test of the season, Romano was the latest player struck down.
"That might be four cases we've had and all of them have been vaccinated," Hansen said. "I learnt something the other day about that – they combined the vaccines with the measles and it's not so effective. If you're between the ages of eight and 30 you're vulnerable so I'm just missing out."
Hansen also confirmed captain Kieran Read continued to battle the debilitating disc issue in his back which ruled him out of the Welsh test and confined him to a bed during the backend of the week.
Sam Whitelock assumed the captaincy in Read's absence and Luke Whitelock slotted in at No 8.
"It's not going that great. His back is pretty sore but that is no more than what we expected with what he has got. He just needs a bit of time to get over that and he'll be fine."
