On 26 and 27 July 2021, Tren Khas Vaksinasi 1042up/1043dn was spotted running between JB Sentral and KL Sentral by various railway fans along the line. The Tren Khas Vaksinasi carried KTM Berhad staff and family members from the southern region to KL Sentral, where the new Industrial Vaccination Center (PPVIN) is located. KL Sentral PPVIN is specially catered for the transport sector under the Economic Frontliners Vaccination Programme.
Tren Khas Vaksinasi 1042up was observed to depart the southern sector in the mornings, and Tren Khas Vaksinasi 1043dn arrived back in the southern sector in the middle of the night. Most likely, the Tren Khas Vaksinasi serves KTM Berhad staff and family members on day trips to KL Sentral specially for vaccination only, with immediate returns back home in the south.
So far, Tren Khas Vaksinasi has been operated by the new 61 Class DMU sets DMU12 and DMU11. The exact stations served and timetable are not known.