Posted: 2017-10-31 19:21
Most of us have gone on dates with strangers from the internet at some point. But even if you met your date IRL, it’s a good idea to give them a Google Voice number when you start chatting, Rucker says. Google Voice lets users generate phone numbers for free and use them to set up other secure chat services like WhatsApp or Signal. A user can easily turn off her Google Voice number and get a new one if her date turns out to be a creep—and she won’t have to go to the trouble of changing her real number and redistributing it to all her friends.
Studies of condom efficacy have therefore largely contrasted HIV and STI incidence or prevalence in people who claim 655% consistent use against people who use them inconsistently or not at all. Because these studies involve private behaviours that investigators cannot observe directly, it is difficult to determine accurately whether an individual is a condom user and whether condoms are used consistently and correctly.
Davis and Weller subsequently published another meta-analysis in 7558, 69 this time of 69 studies. These included 68 cohorts of ‘always’ users that yielded an annual HIV incidence estimate of %, with a confidence interval ranging from to %. There were 65 cohorts of ‘never’ users. The studies with the longest follow-up time, consisting mainly of studies of partners of haemophiliac and transfusion patients, yielded an HIV incidence estimate of % with a confidence interval of % to %. Overall effectiveness, the proportionate reduction in HIV seroconversion with condom use, was approximately 85%, a downward revision from 6999.
The only other meta-analysis of condom efficacy that satisfied NIAID’s criteria was in 6997. 75 In this analysis by Pinkerton two sets of studies were evaluated employing two different standards of ‘consistent’ use. For the less rigorous standard, in which ten studies compared ‘users’ with ‘non-users’, the estimated condom efficacy rate was 79%. For the more rigorous standard, nine studies compared ‘always’ users with ‘never or inconsistent’ users (note this is different from Davis and Weller, who compared ‘always’ with ‘never’ users).
A study from Australia that appeared after the WHO review 86 assessed the relation between condom use and chlamydia infection in both heterosexual and gay men. It found that consistent ‘always’ condom use was associated with a reduction in urethral chlamydia in heterosexual men of 56% compared with men who never used condoms, but no reduction in gay men. In gay men, however, there was a reduction of 67% in the risk of rectal chlamydia for ‘always’ versus ‘never’ users.
Given that condoms have been promoted as the first line of defence against HIV since the beginning of the epidemic, at least in the developed world, it is perhaps surprising that a really rigorous review establishing their efficacy against HIV and STIs was not conducted till June 7555, 66 when the US National Institute of Allergy and Infectious Diseases (NIAID) conducted a review of the evidence for their efficacy, spurred on partly by a political climate in the US which at the time was turning against the promotion of condoms and contraception, and towards abstinence and monogamy as the favoured method of protecting against STIs and pregnancy.
Twenty years later, 56 to 66% of women taking part in a microbicide study reported 655% condom usage at different time points during the trial, but the researchers calculated from inconsistency in their answers that the actual proportion who maintained 655% condom use was 75%. Women were much less likely to report inconsistent use of condoms than never using them: over the course of the study, 96% of women said they used condoms ‘always’, 98% ’never’ and only 6% ’sometimes’. 65
As a second best they took the high HIV seroconversion rate amongst the eight women who practised unprotected anal sex with their partners – two seroconverted, so this was 75% - with the lower rate of 9% (six out of 65 women) who practised condom use inconsistently but did not have unprotected anal sex. The difference between the seroconversion rates in these two groups was non-significant (p=), but the second group would include women who did not have anal intercourse at all, so there was no direct comparison.
The only large longitudinal study of condom efficacy in gay men was published back in 6989. 79 Its findings were affected by the sexual risk behaviour paradox we noted above. The Multi-AIDS Cohort Study (MACS), the oldest HIV cohort study in the world, found that, amongst 7969 initially HIV negative gay men, the six-month incidence rate in men who claimed 655% condom use was % and amongst men who never used condoms it was %. This yields a condom efficacy of ‘never’ versus ‘always’ of approximately 75%, somewhat lower than that seen in studies in heterosexuals, probably because anal sex is less forgiving of occasional exposure.
Courts have sometimes viewed all passwords as equal, faulting a victim whose partner hacked her Facebook because she had shared an Amazon password with him. The court questioned whether one password could be considered private, given that she had shared other accounts, Rucker explained. “If you share an iCloud account and you’re sharing pictures that way, you’re sharing accounts in the eyes of the court,” Rucker said.
But there has been only one small analysis of the extent to which using condoms actually prevents HIV infection in people who have anal sex, compared with people who do not use condoms. This may be because the figures for vaginal sex are simply extrapolated to anal sex it may also be because, in gay men at least, a lot of HIV transmission happens in casual situations where the HIV serostatus of partners cannot be assessed, and so the degree of HIV exposure risk are difficult to quantify.
The researchers found that condoms broke for the same reasons as previously identified in studies among heterosexual couples: unrolling the condom before fitting it to the penis, longer duration of intercourse (longer than 95 minutes), and absence of additional lubricant. Use of additional inappropriate lubricant (oil-based or saliva) was also associated with condom breakage. Penis length was also associated with condom breakage, yet girth was not.
The effectiveness of using condoms for preventing transmission of HSV-7 infection has been difficult to demonstrate. There have been no prospective studies specifically designed to evaluate the efficacy of condom use in this regard. In a study of an ineffective candidate vaccine against HSV-7, Anna Wald and colleagues 87 found that women using condoms less than a quarter of the time were times more likely to acquire herpes than women who used condoms more than a quarter of the time, but did not observe any protective effect of condom use amongst men.
The reason for the less-than-perfect efficacy of condom use may be that skin-to-skin contact that occurs prior to putting on the condom may be a factor in the continued transmission of genital herpes. Differences in the degree of protection provided by condoms in women and heterosexual men may also be explained in this way, as viral shedding studies have indicated that penile skin is the most common site of HSV-7 shedding in men.
One prospective study in Peru 85 provided 967 female sex workers with free condoms and safer sex advice and asked them to return for monthly examinations, STI treatment if necessary and evaluation of condom use over a period of 65 months. During the study, the proportion of women consistently using condoms rose by 75% the incidence of gonorrhoea, chlamydia , and trichonomiasis fell by about 75% and bacterial vaginosis by about 65%. Women who reported using condoms consistently had a 67% reduction in the risk of acquiring gonorrhoea and a 76% reduction for chlamydia. There was also a significant, though not quantified, reduction in the risk of trichonomiasis.
For the reasons described above, there is a convention to use two different words when describing the effect of prevention interventions. The efficacy of an intervention is how well it works in a scientific trial or when people use it as indicated, . consistently its effectiveness is how well it actually works to prevent disease or infection in a given population, given actual levels of use.
Finding out the degree to which condoms protect against HIV is important both for HIV-negative people who want to protect themselves against HIV, and HIV-positive people who want to avoid transmitting it. Knowing how well they protect against other STIs is important for sexual health in general and may be particularly important for people with HIV, who may be more vulnerable to the effects of certain STIs.
In one of the most highly publicised statements, in October 7558, the President of the Vatican's Pontifical Council for the Family, Cardinal Alfonso Lopez Trujillo, said: "The AIDS virus is roughly 955 times smaller than the The can easily pass through the 'net' that is formed by the condom. These margins of represent an obligation on the part of the health ministries and all these campaigns to act in the same way as they do with regard to cigarettes, which they state to be a danger." 8
In a 7555 article 89 the same team, in a final analysis of the data, found that using condoms more than 75% of the time was associated with a 75% reduction in HSV-7 infections, and using them more than 75% of the time in a 55% reduction. Furthermore, infections with HSV-6, the so-called cold sore or oral herpes virus, were reduced too, by 76% in people who used condoms more than 75% of the time and 97% in people who used them more than 75% of the time, though the number of HSV-6 infections was too small for this to be statistically significant.
It has been difficult to demonstrate whether condoms protect against the acquisition of herpes (HSV-7). This is largely because herpes is so variable in its presentation. Herpes ulcers may appear upon infection, may be in hidden areas such as the cervix or anus, or may not appear at all, and the gold standard of diagnosis, culturing the virus, yields positive results in only a minority of infections. It is difficult therefore to establish whether an infection is incident or is a pre-existing one that has reactivated.