We present a significant update of the constraints on the Abelian Higgs cosmic string tension by cosmic microwave background ( CMB ) data , enabled both by the use of new high-resolution CMB data from suborbital experiments as well as the latest results of the WMAP satellite , and by improved predictions for the impact of Abelian Higgs cosmic strings on the CMB power spectra . The new cosmic string spectra [ ] were improved especially for small angular scales , through the use of larger Abelian Higgs string simulations and careful extrapolation . If Abelian Higgs strings are present then we find improved bounds on their contribution to the CMB anisotropies , f _ { 10 } ^ { AH } < 0.095 , and on their tension , G \mu _ { AH } < 0.57 \times 10 ^ { -6 } , both at 95 % confidence level using WMAP7 data ; and f _ { 10 } ^ { AH } < 0.048 and G \mu _ { AH } < 0.42 \times 10 ^ { -6 } using all the CMB data . We also find that using all the CMB data , a scale invariant initial perturbation spectrum , n _ { s } = 1 , is now disfavoured at 2.4 \sigma even if strings are present . A Bayesian model selection analysis no longer indicates a preference for strings .