Yes, the NEBNext ARTIC Human Control Primer Pairs 1 and 2 are optional internal controls. If used, the appropriate NEBNext ARTIC Human Control Primer Pairs and NEBNext VarSkip Short v2 SARS-CoV-2 Primer Mix should be combined prior to use. Human Control Primer Pairs 1 can be combined with NEBNext ARTIC NEBNext VarSkip Short v2 SARS-CoV-2 Primer Mix 1 and Human Control Primer Pairs 2 can be combined with NEBNext ARTIC NEBNext VarSkip Short v2 SARS-CoV-2 Primer Mix 2.
NEBNext ARTIC Human Control Primer Pairs generate 400 bp amplicons, while VarSkip Short v2 amplicons are ~550bp. After enzymatic fragmentation Human Control and VarSkip Short v2 SARS-CoV-2 fragment sizes are both ~120 bp.