Hope for a CMV vaccine

Cytomegalovirus, or CMV for short, belongs to the herpesvirus family, along with the herpes simplex, Epstein-Barr, and chickenpox virus. It causes a mononucleosis-like disease similar to EBV, mainly in teens and young adults (they don’t call it ‘the kissing disease’ for nothing!), and in children the primary infection may have no symptoms at all or mimic another viral infection. Like all herpesviruses, it stays in the body indefinitely, occasionally and asymptomatically entering the bloodstream and other bodily fluids. Transmission to another person is usually accomplished by sharing utensils, kissing, and rarely via blood products. In immunosuppressed people, CMV (either primary infection or reactivation) can cause very severe and life-threatening infections.

However, the most common form of damage caused by this virus happens when a woman is primarily infected with CMV in early pregnancy, or if the virus reactivates at that point (which is probably somewhat less risky). According to the CDC:

* Between 50% and 80% of adults in the United States are infected with CMV (cytomegalovirus) by 40 years of age

* CMV is the most common virus transmitted to a pregnant woman’s unborn child

* Approximately 1 in 150 children is born with congenital CMV infection

* Approximately 1 in 750 children is born with or develops permanent disabilities due to CMV

* Approximately 8,000 children each year suffer permanent disabilities caused by CMV

* Congenital CMV (meaning present at birth) is as common a cause of serious disability as Down syndrome, fetal alcohol syndrome, and neural tube defects.

Congenital CMV is the most common cause of congenital non-heritable deafness and cerebral palsy, and the second most common cause of mental retardation (after Down Syndrome) in the developing world.

Though many women have already had CMV by the time they reach reproductive age (here in Israel, more so than in the US), I managed to remain CMV negative and as far as I know, still am. When I was having babies, I had to keep on reminding the OB to test and retest me for CMV during pregnancy, just in case I’d acquired it (and let’s face it – in my line of work, I am at high risk of doing so). Nowadays, at least in the clinic I work in, we’ve made testing for CMV and toxoplasma (another microorganism which can cause severe birth defects) routine.

I’ve often wished there was a CMV vaccine available. After all, you need it for the same reasons as the rubella vaccine. Now, it seems I may one day get my wish:

In a manufacturer-supported phase II study of CMV glycoprotein B vaccine with MF59 adjuvant, investigators randomized 464 CMV-seronegative postpartum women to receive three doses of vaccine (at baseline, 1 month, and 6 months) or placebo within 1 year after delivery. Participants were followed for ≤42 months. CMV acquisition was determined with viral culture, polymerase chain reaction assay, or antibody testing, and women used diaries to report adverse events.

Overall, 8% of vaccine recipients and 14% of placebo recipients acquired CMV during follow-up (P=0.02); vaccine efficacy was 50%. Congenital CMV infection occurred in 1 of 81 infants (1%) born to all vaccine recipients and 3 of 97 infants (3%) born to all placebo recipients (P=0.41). The vaccine was moderately reactogenic: Incidence of myalgias, arthralgias, and chills was higher in the vaccine group than in the placebo group. After the third dose, 3% of vaccine recipients reported severe injection-site pain.

Comment: These results show that even a single-antigen CMV vaccine can provide substantial protection to postpartum women; moreover, such protection might translate into lower rates of congenital CMV infection. In general, this vaccine has lower efficacy than others already on the market — 50% versus at least 90% for most vaccines — and is moderately reactogenic, probably because of the MF59 adjuvant. However, these results raise hopes for development of a successful CMV vaccine.

The abstract of the study commented on is here.

And here’s the layperson’s audiovisual version, courtesy of the University of Alabama at Birmingham:

More great resources on congenital CMV:

Stop CMV, which has these cool banner ads directing pregnant women how to avoid CMV infection (which are, alas, too large to put in this post)

The Congenital CMV Foundation

The Brendan B. McGinnis Congenital CMV Foundation

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8 Responses

  1. All the doctors working with Meuchedet [which are the ones I know] order CMV testing as part of the routine blood work done on newly-pregnant women. My guess is that it’s pretty standard in Israel, since many doctors work with more than one kupah [health fund]

  2. Wow, I never knew that about Cytomeglia virus and pregnancy. I took care of a huge number of Cytomeglia patients at the big world renoun hospital I worked at as a new nurse grad. Should I get checked? Is the vaccine avaiible in the USA? SHould I get my boy vaccinated? He is 10. I should probaby get my daughter vaccinated, she is 24. Good post. Lots to think about. Thanks

    • There is no vaccine yet, Pinky. But they’re in the advanced stages of working on one. Pregnant women (or those planning pregnancy) should ascertain their CMV status and if negative, take precautions (not share drinks, be sure to wash hands frequently, not kissing other people’s kids etc).

  3. CMV was never mentioned during either of my pregnancies. I only knew about it because the blood bank I donate to contacted me to request additional donations due to my CMV-neg status–they said because I was 0-neg and CMV-neg, I could give to neonates. I did a bit of reading (this was before I matriculated at Google U) and got thoroughly freaked out. Wish there had been a vaccine–would have save me some worries.

  4. What I wouldn’t give for this!!

    I am a teacher. Two years ago when I was pregnant I had two kids out for a week and a half. Then they come back but are obviously still sick. Turns out they had CMV and their parents were just sick of having them at home only being “somewhat under the weather.” So they shipped them back to school where I had to come in contact with them for hours a day. When I found out it was CMV I called to get my status to see if I sure worry. Sure enough it was CMV negative. I don’t know how I’ve managed to stay in this profession this long and still be negative, but I lived in fear for quite some time that I would get infected. Don’t send your kids to school sick!!

    I wish I could be infected now so that I can have another baby and not have the same fear.

    So I guess I am CMV- and O-. I should be giving neonate blood too, eh?

  5. another cmv- here, I am O+, not as good as O- but still desirable enough when I donate blood. For this pregnancy I got retested for CMV but the nurse or the doctor didn’t mention anything about it or about preventing CMV during pregnancy. But, again, I am usually disappointed at the care that I receive from the clalit nurses at my clinic, so what can I expect. This last winter I almost had to force the nurse from Tipat Chalav to give my daughter (2.5 years) the flu vaccine. When I asked the metapelet (nursery teacher) and other moms of kids that age, none of them 1) knew the difference between flu and a regular cold. 2) knew there is a flu vaccine or anything about it. 3) got it for themselves or their kids. Being an educated person is a must where I live…

    • The blood bank is usually very happy to get my B+, CMV- blood as well.

      Rachel – why did you get the flu shots at Tipat Chalav? We give them in the kupah for free (I work for Clalit as well). In fact, we were begging and calling people all winter to come and get their flu shots!

  6. Because her next tipat chalav appointment fell around the beginning of the flu season. I didn’t get it myself becaseu the OB said better not during the first trimester, but I got it for my daughter and forced husband to get it.
    No same blood bank would turn away any elegible donor, but some blood is separated into the components (platelets, etc) and some blood they prefer to leave whole for blood transfusions. When I was donating in the states they told me that an O+ CMV- would never be separated into their components because it’s to close to universal donor. In my family I seem to be the only one with the guts to donate and get the “blood insurance” so I do it happily when I can.

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