On March 4, a man in London, became the second person to be "cured" of HIV. Chai Knows, a popular science micro blog account, comments:

Eighteen months after the patient received his last treatment, he is virus-free. His doctor has advised him not to take any more medicine and to remain under observation.

If it is still too early to say he has been cured, it is at least safe to say he is "almost cured".

Together with the good news came two questions: Is it possible to cure AIDS? Can the method be applied widely?

The first question has had an answer for at least 10 years: Yes. As early as 2009, another AIDS patient from America was confirmed to have been virus-free after having a bone marrow stem cell transplant in Germany to treat his cancer. He became widely known as the "Berlin Patient". This time, certain media outlets have already been calling the second patient the "London Patient".

The answer to the second question is, unfortunately, "No". Both the Berlin Patient and the London Patient received a kind of old treatment, namely a bone marrow stem cell transplant, which has very complicated requirements, and has a very low success rate. In plain words, the treatment involves high cost, high risk, and has a low success rate.

While the Berlin Patient found a donor match, other patients with acute myeloid leukemia are unable to find a donor whose stem cells match theirs. The Berlin Patient was lucky to have found 267, and one of them happened to carry a CCR5 genetic mutation, which strengthens human protection against HIV.

Then he survived all the treatments, each of which could have killed him. He survived long-term chemotherapy treatment, survived the recurrence of AML, and finally defeated the virus. The total treatment cost is not known yet, but it is undoubtedly unbearable for any ordinary family.

The treatment details for the London Patient have not been made public yet. But one thing is certain: He received treatment similar to the Berlin patient.

There is still a long way to go, but the two patients offer hope that CCR5 gene-editing or antibody techniques can one day be applied on a wide scale as a cure for HIV.