Unfortunately this investigation from Oxford University does not provide a true information about HIV spreading. People newly infected with the virus do not have viral load in thier bloodstream and enough amount of infected lymphocytes also to transfer their just-obtained virus to the others including drug-using or sexual partners. Infection itself is even possible to detect after 3-4 months, not talking about chances of its "successful" transmission to the others. So, the transmission is going on in next several years after obtaining it through the needle, and several years before the person starts to feel AIDS sympthoms and became aware of his\her diagnosis, then starts therapy, are normally 5-7 years. It is nonsense about ONE MONTH period to transmite HIV after obtaining it.