US Vice President JD Vance and Second Lady Usha Vance on Sunday announced the birth of their fourth child, the first baby born to a sitting US vice president in more than 150 years.The couple welcomed a baby boy, Alec Neel Vance, who joins siblings Ewan, 9, Vivek, 6, and Mirabel, 4.Announcing the birth on social media, the couple said, “We are excited to announce that our baby boy, Alec Neel Vance, was born this morning. Usha and the baby are happy and healthy, and our kids are overjoyed to meet their little brother.”They also thanked the doctors and staff at the Walter Reed National Military Medical Center and the White House medical team for their care.