The prevalence of cervical infection with HPV type 16 and/or 18 among married women in this study ranged from 3.1% to 7.4%. This prevalence was highest in Can Tho, this figure was also consistent with the fact that among 5 cities, Can Tho had highest rate of cervical cancer . Most of HPV positive cases in this study were infected with HPV type 16 or 18. So this finding was similar to previous studies in Vietnam and other countries [8, 11, 12].
Results also indicated that among cases with abnormal Pap results, 16.9% of them infected with HPV 16 and/or 18; however, the sample size of women with abnormal Pap smear was not sufficient enough to examine the distribution of HPV 16 and/or 18 among abnormal Pap cases. Data about the composition of HPVs present in cervical cancer in Vietnam was also not available from previous research. It is important to note that the distribution of HPV type 16/and or 18 among general population would be different to that among cancer cases. So the distribution of HPV 16/and or 18 among general married women in this study cannot be considered as a proxy for that in cervical cancer and it was a limitation of this study.
In addition to HPV 16 and 18, this study also reported 14 other types of high risk HPV, most notably was HPV type 58, 52, 35 and 45. Other studies also reported that HPV 58 was among the most common types found in cervical cancer specimens in China, Thailand and The Philippines . A recent meta analysis about HPV positive and cervical cancer had showed that HPV45 (in Africa and South/Central America) and HPV 58 (in Eastern Asia) accounted for important proportions of HPV-positive CIN2 and CIN3 . HPV58 and HPV45 were also common high risk type in Vietnam. The current available vaccines may have cross-protective effects against 4 types, HPV-33, HPV-31, HPV-45, and HPV-51, in addition to HPV 16 and 18  but no evidence about the protective effects with HPV 58 has been reported. Thus, while it is relevant to implement an HPV vaccine campaign in Viet Nam due to the high prevalence of infection with HPV 16 and/or 18, it is also important to inform the women who receive the vaccines that they are not protected against all high risk HPV types and that they still need cervical cancer screening. A recent study also showed that two doses of the HPV16/18 vaccine, and maybe even one dose, are as protective as three doses . As the current three-dose regiments for HPV vaccines are expensive and difficult to complete, the vaccine campaign in Vietnam may consider to offer the two dose regiment instead.
Vietnam still applies the opportunistic cytology-based screening model and this model has failed to have an impact on the overall incidence of cervical cancer in Vietnam. A new potential model “screen and treat” using either HPV DNA testing or VIA (visual inspection with acetic acid) followed by treatment with cryotherapy (freezing) proposed by the Alliance for Cervical Cancer Prevention may be applied to the Vietnam context .
Results showed that about 37.4 women ever heard about HPV and 31.2% knew about HPV vaccine. A previous study among women in the United states reported that the level of awareness of HPV and of HPV vaccine were 84.3% and 78.9% . More comparable, a study among the rural folks in Penang Malaysia estimated that about 42.2% women ever heard about HPV vaccine . So compared to other countries, the level of HPV and HPV vaccine awareness were limited, in order to make the vaccine campaign become more effective, Vietnam need to have more mass media campaign to provide more information about HPV and HPV vaccines.
Strict protocols to avoid biases were followed in this study: women were randomly chosen, all clinical examination and specimen collections were done by qualified gynaecologists and all the samples were examined by a nationally qualified laboratory. The detection of HPV positivity using real time PCR methods and the genotyping of HPV type using reverse dot blot method in this study also provided more precise results compared to the Hybrid Capture Tube Method applied in previous studies . One also may question while the target of HPV vaccination should be adolescents and this study captured mostly women over 30 year old.
This is a limitation of this study because we were not able to invite unmarried women to attend study with pelvic examinations and cervical sampling collect due to the strict cultural/ethical norms in Vietnam so the results did not cover a subgroup a the young population already sexually active but not yet married. It can also be argued that probably HPV detected in older women would have more likely to be present for a longer period, at higher risk of persistent infection and higher risk to develop lesions and cancer so the data presented in this study would be very useful for the cervical screening programming in Vietnam.