"Recent years have seen a decline in the use of retroviral vectors (currently, only 19.7% of trials compared to 22.8% in 2007 and 28% in 2004), presumably as a result of the severe adverse events observed in the SCID trials, and research is well underway towards engineering safer retroviral vectors. Adenoviruses are the most commonly used vector (23.3% of all trials)". From Ginn et al. The paper is free here https://www.researchgate.net/publication/235377142_Gene_therapy_clinical_trials_worldwide_to_2012_-_an_update?ev=srch_pub&_sg=0kuhTM7mdLSNcFCqpave%2FFokSjoKfCqUx9VdoVkGPAWfIEy7DFjp5kbHzyu%2FpGhb_jzpfkQaU5PeZB%2BeoH9jOl1WlWGKNjNlSFAKkpgkUNilM5BJ1aywW0EBQ8ILj9MK6_mDsIAWi7Xxzsd6Y36DXmPnoUj5SJWLJbllPLzZZ7C97CwrMe4%2Bukb1G%2Ba%2FYE%2FpZL
Article Gene therapy clinical trials worldwide to 2012 – An update
In cancer gene therapy AAVs have bene successfully used, being superior to other vectors for weak toxicity and long term gene expression. Have a look at this review
Best regards stefania
Article Adeno-Associated Virus-Mediated Cancer Gene Therapy: Current Status
Actually it depends on which disease and cell type you are working on. Some vectors are better in cancer, while other types are superior in cardovascular diseases.
However, it wouldn't be surprising to find Adenovirus, AAV, retrovirus, lentivirus, baculovirus etc. are the most common viral vectors in gene therapy.
Manar, Vectors based on adeno-associated viruses (AAVs) have emerged as safe and effective and, in one recent case, have led to regulatory approval. In cancer gene therapy AAVs have bene successfully used.