如果乙型肝炎被性传播，我的合作伙伴如何感染？

StephenW

Hep B Blog
Living with Hepatitis B
If Hepatitis B Is Sexually Transmitted, How Come My Partner Isn’t Infected?
February 1, 2017 hepbtalk   

By Christine Kukka

I thought hepatitis B was sexually transmitted? I just tested positive, but my partner tested negative, we’ve been together for years, what gives?

This question is a common one. Hepatitis B is indeed easily transmitted sexually, so why do some people — who were not vaccinated — never get hepatitis B from their sexual partners?

It comes down to variables, such as the type of sexual activity you engage in, the viral load (HBV DNA) of the infected partner, and who is on the receiving end of infectious body fluids, especially blood that contains the most virus and semen.

Having one partner infected, and other not, can add more stress to an already traumatic hepatitis B diagnosis. “It was very confusing and made me question how was it possible I was the only one infected,” said a woman who tested positive while her husband tested negative.  “I thought it was possibly a mistake, maybe I was a biological anomaly, which of course I was not.”

Let’s look at the factors that affect who gets infected and who doesn’t when two people have sex.

Viral load: Semen, vaginal fluids and blood all contain the hepatitis B virus (HBV), and the higher the viral load, the more infectious one’s blood and body fluids are. However, having an undetectable viral load doesn’t mean you won’t infected someone during unsafe sex. Even if a man has an undetectable viral load, studies show his semen still contains some HBV and can spread infection, though the risk is lower.

So the rule here is if a man tests positive for the hepatitis B surface antigen (HBsAg), he must consider himself infectious.

The role of gender: In heterosexual relationships, uninfected women are at higher risk of getting infected by a male partner infected with hepatitis B, than the reverse. Women are on the receiving end of semen, which greatly increases their risk of becoming infected unless a condom is used.
Image courtesy of renjith krishnan at FreeDigitalPhotos.net.
Image courtesy of renjith krishnan at FreeDigitalPhotos.net.

When a woman is infected with hepatitis B, an uninfected man is at risk through direct contact with her vaginal secretions, but that contact is lower-risk than a woman’s direct exposure to infectious semen during intercourse.

However, an infected woman who is menstruating is more likely to spread hepatitis B because blood can contain higher levels of HBV than vaginal secretions. That is why gloves and dental dams are recommended to provide a barrier against exposure.

The type of sexual activity: Certain sexual activities are far more efficient at spreading hepatitis B than others. Oral sex appears to have a lower rate of hepatitis B transmission than vaginal sex. Anal sex carries a very high risk of transmission because of tears in the skin that can occur during penetration improves transmission of HBV.

Fingering carries a lesser risk, unless the infected woman is menstruating or a person has bruises or cuts on their hands that allow entry to hepatitis B in semen or vaginal fluids, then gloves are recommended.

The “uninfected” partner could already have been infected and cleared hepatitis B: When a person is first diagnosed with hepatitis B, doctors often test his or her partner for only the hepatitis B surface antigen (HBsAg), which indicates a current hepatitis B infection. If they are negative for HBsAg, they are immediately vaccinated.

If the partner isn’t also tested for the hepatitis B surface antibody (anti-HBs or HBsAb), then no one knows if  the individual was infected years ago (or earlier in the relationship) with hepatitis B and cleared the acute infection.

Hepatitis B is not called the “silent” infection for nothing — many people who get hepatitis B never have any symptoms and never realize they were infected. As a result, a wife, husband, partner or lover who tested negative for HBsAg, may actually have been infected in the past and cleared the infection and now has protective hepatitis B surface antibodies to forever safeguard them from infection. If they’re immediately vaccinated and retested after the three-dose vaccination, they will test positive for surface antibodies, without ever knowing that their antibodies resulted from a past infection, not immunization.

Bottom line, if one of you have been diagnosed and the other is not infected, it is unusual but not uncommon. Get tested and immediately vaccinated if the uninfected partner tests negative for the hepatitis B surface antibody.

StephenW

乙肝博客
生活与乙型肝炎
如果乙型肝炎被性传播，我的合作伙伴如何感染？
2017年2月1日hepbtalk

作者：Christine Kukka

我认为乙型肝炎是性传播的？我只是测试为阳性，但我的合作伙伴测试为阴性，我们已经在一起多年，什么给了？

这个问题是很常见的。乙型肝炎确实容易性传播，所以为什么一些人 - 谁没有接种疫苗 - 从来没有得到乙型肝炎从他们的性伴侣？

它归结为变量，例如你从事的性活动的类型，感染的合作伙伴的病毒载量（HBV DNA），以及谁在传染性体液，特别是含有最多的病毒和精液的血液。

有一个伙伴感染，而另一个没有，可以增加更多的压力，已经创伤的乙型肝炎诊断。 “这是非常混乱，使我问我怎么可能我是唯一的一个感染，”一个女人测试结果为阳性，而她的丈夫测试为阴性。 “我认为这可能是一个错误，也许我是一个生物异常，当然我不是。

让我们来看看影响谁受到感染的因素，以及当两个人发生性行为时，谁不知道。

病毒载量：精液，阴道液和血液都含有乙型肝炎病毒（HBV），病毒载量越高，感染者的血液和体液就越多。然而，具有不可检测的病毒载量并不意味着你不会在不安全的性行为时感染某人。即使一个人具有不可检测的病毒载量，研究显示他的精液仍然含有一些HBV，并且可以传播感染，尽管风险较低。

所以这里的规则是如果一个人测试乙型肝炎表面抗原（HBsAg）阳性，他必须考虑自己感染。

性别的作用：在异性性关系中，未受感染的女性感染乙型肝炎的男性配偶感染的风险较高，反之亦然。妇女是精液的接受端，这大大增加了他们感染的风险，除非使用避孕套。
图片由renjith krishnan提供FreeDigitalPhotos.net。
图片由renjith krishnan提供FreeDigitalPhotos.net。

当女性感染乙型肝炎时，未感染的人通过与她的阴道分泌物直接接触而处于危险中，但是该接触比女性在性交期间直接接触感染性精子的风险低。

然而，经期感染的妇女更可能传播乙型肝炎，因为血液可以含有比阴道分泌物更高水平的HBV。这就是为什么建议手套和牙坝提供防止暴露的屏障。

性活动的类型：某些性活动在传播乙型肝炎方面比其他活动更有效。口交性似乎具有比阴道性更低的乙型肝炎传播率。肛交具有非常高的传播风险，因为在渗透期间可能发生的皮肤撕裂改善HBV的传播。

手指带有较小的风险，除非受感染的妇女月经或一个人在他们的手上有瘀伤或切口，允许进入乙型肝炎在精液或阴道液体，然后推荐手套。

“未感染”的合作伙伴可能已经感染和清除乙型肝炎：当一个人首次被诊断患有乙型肝炎时，医生经常只测试他或她的伴侣只有乙型肝炎表面抗原（HBsAg），这表明目前的乙型肝炎感染。如果他们是HBsAg阴性，他们立即接种疫苗。

如果合作者还没有测试乙型肝炎表面抗体（抗HBs或HBsAb），那么没有人知道该个体是否在几年前（或在关系中较早）感染了乙型肝炎，并清除了急性感染。

乙型肝炎不被称为“沉默”感染的无 - 许多人谁得到乙型肝炎从来没有任何症状，从来没有意识到他们感染了。结果，对HBsAg阴性的妻子，丈夫，伴侣或恋人可能实际上在过去已感染，清除感染，现在有保护性乙型肝炎表面抗体，永远保护他们免受感染。如果他们立即接种疫苗并在三剂疫苗接种后重新测试，他们将测试表面抗体阳性，而不知道他们的抗体是由过去的感染，而不是免疫。

底线，如果你的一个被诊断出来，另一个没有感染，这是不寻常的，但并不罕见。如果未感染的伴侣对乙型肝炎表面抗体检测阴性，进行测试并立即接种疫苗。