Varicella (Chickenpox)

Varicella developed in 25 of 88 children (28.4 percent) between
December 1, 2000, and January 11, 2001. The index case occurred in a
healthy child who had been vaccinated three years previously and who infected
more than 50 percent of his classmates who had no history of varicella. The
effectiveness of the vaccine was 44.0 percent (95 percent confidence
interval, 6.9 to 66.3 percent) against disease of any severity and 86.0
percent (95 percent confidence interval, 38.7 to 96.8 percent) against
moderate or severe disease. Children who had been vaccinated three years
or more before the outbreak were at greater risk for vaccine failure than
those who had been vaccinated more recently (relative risk, 2.6 [95 percent
confidence interval, 1.3 to 5.3]).

Conclusions In this outbreak, vaccination provided poor protection against varicella, although there was good protection against moderate or severe disease. A longer interval since vaccination was associated with an increased risk of vaccine failure. Breakthrough infections in vaccinated, healthy persons can be as infectious as varicella in unvaccinated persons.

Outbreak of Varicella at a Day-Care Center despite Vaccination


Karin Galil, M.D., M.P.H., Brent Lee, M.D., M.P.H., Tara Strine, M.P.H.,
Claire Carraher, R.N., Andrew L. Baughman, Ph.D., M.P.H., Melinda Eaton,
D.V.M., Jose Montero, M.D., and Jane Seward, M.B., B.S., M.P.H.

According to University of Maryland Medical Center, Chickenpox outbreaks are occurring in the vaccinated

Experts pushed for the new second-dose policy due to a number of recent chickenpox outbreaks among previously vaccinated schoolchildren.

A 2007 study in the New England Journal of Medicine also found that one dose of the vaccine may not be enough to provide complete immunity. Among 350,000 patients researchers studied over 10 years, 11,356 were reported to have chickenpox. A total of 1,080 of the patients had breakthrough disease, a modified form of chickenpox with a mild rash that can occur in some vaccinated people. According to the study, those most at risk were children ages 8 – 12 years who had been vaccinated at least 5 years before their current chickenpox infection.

They also state:

Side Effects of the Varicella (Chickenpox) Vaccine

* Discomfort at the Injection Site. About 20% of vaccine recipients have pain, swelling, or redness at the injection site.
* Severe Side Effects. Only about 5% of adverse reactions are serious. Such events include seizures, pneumonia, anaphylactic reaction, encephalitis, Stevens-Johnsons syndrome, neuropathy, herpes zoster, and blood abnormalities.
* Risk of Transmission. The vaccine may produce a mild rash within about a month of the vaccination, which can transmit chickenpox to others. Individuals who have recently been vaccinated should avoid close contact with anyone who might be susceptible to severe complications from chickenpox until the risk for a rash passes.
* Later Infection. Months or even years after the vaccination, some people develop a mild infection termed modified varicella-like syndrome (MVLS). The condition appears to be less contagious and has fewer complications than naturally acquired chickenpox.


Transmission of varicella-vaccine virus from a healthy 12-month-old child to his pregnant mother. She had an abortion and the baby turned out to be unaffected. Total waste of human life.

A 12-month-old healthy boy had approximately 30 vesicular skin lesions 24 days after receiving varicella vaccine. Sixteen days later his pregnant mother had 100 lesions. Varicella-vaccine virus was identified by polymerase chain reaction in the vesicular lesions of the mother. After an elective abortion, no virus was detected in the fetal tissue. This case documents transmission of varicella-vaccine virus from a healthy 12-month-old infant to his pregnant mother.

J Pediatr 1997 Jul;131(1 Pt 1):151-4 Department of Pediatrics, University of California, Los Angeles School of Medicine, USA.

VAERS Reports Of Chickenpox After Varicella Vaccine – It Isn’t Always Milder In The Vaccinated!

VAERS ID 74810

A 6 year old boy was vaccinated with varicella vaccine and he developed varicella 13 days after the vaccine, which then developed into pneumonia.

VAERS ID 75212

A 3 year old girl was vaccinated with varicella vaccine and 8 days later she got varicella.

pt recv vax; rash noted 8 days p/ vax, greater than 50 varicella eruptions over trunk, face;low grade fever; very cranky; fever 102.

VAERS ID 75754

A 6 year old boy was vaccinated with varicella vaccine and 13 days later he got varicella.

devel varicella and pneumonia; pt’s hospitalization was prolonged;pt’s MD felt pt may have aspiration pneumonia.

He had numerous pre-existing conditions that should have contraindicated vaccination.

VAERS ID 308573

Two siblings BOTH DIED after varicella vaccine.

It was reported in a published article that a patient was vaccinated with a dose of VARIVAX (Oka/Merck). After vaccination, the patient died two months after receiving a diagnosis of familial hemophagocytic lymphohistioicytosis. An autopsy was not performed. It was reported that the patient’s older sibling died after vaccination with VARIVAX (Oka/Merck) (WAES # 0803USA04484).

Younger age at vaccination may increase risk of varicella vaccine failure. Despite varicella vaccination coverage of 80%, a sizeable outbreak occurred.

To determine vaccine effectiveness (VE), a varicella outbreak in a highly vaccinated day-care center (DCC) population in Pennsylvania was investigated. In Pennsylvania, proof of immunity is required for children >or=12 months old for DCC enrollment. Questionnaires were administered to parents of children who had attended the DCC continuously during the study period (1 November 1999-9 April 2000) to determine history of varicella disease or vaccination and for information about any recent rash illnesses. VE was calculated for children >or=12 months old without a history of varicella. There were 41 cases of varicella among 131 attendees, with 14 cases (34%) among vaccinated children. VE was 79% against all varicella and 95% against moderate or severe varicella. Vaccination at <14 months was associated with an increased risk of breakthrough disease (relative risk, 3.0; 95% confidence interval, 0.9-9.9). Despite varicella vaccination coverage of 80%, a sizeable outbreak occurred. Early age at vaccination may increase the risk of vaccine failure.

Source: J Infect Dis. 2002 Jul 1;186(1):102-5. Epub 2002 Jun 5.

10 Students Diagnosed With Chickenpox – 7 Had Been Vaccinated, 3 Had Not

Seven students at a Mira Mesa middle school and three children at a Santee child care center have been diagnosed with chicken pox, the San Diego County Health and Human Services Agency announced Friday.

None of the infected students at Challenger Middle School or the KinderCare Learning Center required hospitalization, according to the HHSA.

Five of the middle school students had one dose of vaccine; two had no vaccine. Two of the childcare children had one dose of vaccine, one had no vaccine.

Source: nbc San Diego Health,, January 30th 2009.

Prolonged varicella viraemia and streptococcal toxic shock syndrome following varicella vaccination of a health care worker

A 49-year-old health care worker received varicella vaccine in accordance with current Australian guidelines. She developed streptococcal toxic shock syndrome, complicated by acute atraumatic dislocation of the right wrist secondary to poststreptococcal reactive arthritis — to our knowledge, the first report of spontaneous wrist dislocation as a complication in this condition. Vaccination was accompanied by prolonged viraemia with the varicella vaccine strain — also, we believe, the first report of this in an immunocompetent patient.

Source: MJA 2009; 190 (8): 451-453.

38 Cases of Chickenpox…All Had Been Vaccinated Once

A contagious virus has been reported in schools in the Northern Shenandoah Valley, prompting local health officials to work to stop the outbreak.

And, no, it’s not swine flu.

Some 38 cases of chickenpox have been reported in Page County over the past three weeks, according to Dr. Stephen Haering, director of the Lord Fairfax Health District.

Since the introduction of a chickenpox vaccine in 1995, the county has usually seen only five or six cases for an entire year.

But in the past three weeks, “Luray Elementary has had 18 cases and Stanley Elementary has had 17 cases,” said Haering.

The outbreak has prompted calls for Page County students to get a second dose of the vaccine to improve their immunity.

Most children get one dose of chickenpox vaccine as a part of routing immunizations for school.

“The one dose is 70 to 85 percent effective,” he said.

That’s been made painfully clear in Page County.

“All these kids have been vaccinated once,” Haering said. “We’re seeing breakthrough disease, which is why we’re pushing for a second vaccination.”

Source:, 12th May 2009, by Garren Shipley.

84 Vaccinated Children Get Varicella – 53 had 1 dose of vaccine, 25 had 2 doses of vaccine

Background: In June 2006, the Advisory Committee on Immunization Practices (ACIP) expanded its June 2005 recommendation for a second dose of varicella vaccine during outbreaks to a recommendation for routine school entry second dose varicella vaccination. In October 2006, the Arkansas Department of Health was notified of a varicella outbreak among students where some received a second dose during an outbreak-related vaccination campaign in February 2006.

Methods: The outbreak was investigated using a school-wide parental survey with a follow-up survey of identified case patients. Vaccination status was verified using state and local immunization records. Limited laboratory testing confirmed circulation of wild-type varicella, including varicella in 2-dose vaccine recipients.

Results: Vaccination information was available for 871 (99%) of the 880 children. Varicella vaccination coverage was 97% (2-dose, 39%; 1-dose, 58%). A review of the February vaccination clinic found no deficiencies; lot numbers did not differ between cases and noncases. Varicella was confirmed by PCR in 5 (42%) of 12 lesion specimens and by IgM in 1 (6%) of 16 serum specimens. Varicella was reported in 84 children, including 25 (30%) two-dose and 53 (63%) one-dose recipients. Attack rates among 2-dose recipients (10.4%) and 1-dose recipients (14.6%) were not significantly different (RR: 0.72, 95% CI: 0.44-1.15). All 2-dose recipients and 80% of 1-dose recipients reported having 50 or fewer skin lesions.

Conclusion: This outbreak is the first to document varicella in both 1- and 2-dose vaccine recipients; both groups had mild disease. The vaccine effectiveness of 1 and 2 doses were similar.


The Pediatric Infectious Disease Journal:doi: 10.1097/INF.0b013e31819c1041.

Enhanced Chickenpox Exanthema at Vaccine Injection Site

Exacerbation of viral exanthema has been described after different types of aggression. We report a case of enhanced chickenpox exanthema occurring in the vaccination site of an otherwise healthy boy. Specific local inflammatory modifications may explain the increased number of varicella skin lesions on the site of a previous vaccine-induced inflammation.

Source: Scandinavian journal of infectious diseases, 2006, vol. 38, no10, pp. 920-921 [2 page(s).

More Chickenpox Exanthema at Site of FLU Injection

We report the first case of chickenpox exanthema localized to the influenza vaccination site in a boy with known egg allergy.

Source: Pediatric Dermatology, Volume 26, Number 4, July/August 2009 , pp. 481-482(2).

One dose of varicella vaccine does not prevent school outbreaks: is it time for a second dose?
43 Out of 49 Cases Vaccinated

Overall varicella vaccination coverage was 96%. Forty-nine varicella cases were identified; 43 were vaccinated.

Although disease was mostly mild, the outbreak lasted for approximately 2 months, suggesting that varicella in vaccinated persons was contagious and that 99% varicella vaccination coverage was not sufficient to prevent the outbreak.

Varicella outbreaks continue to occur among vaccinated persons. Although varicella disease among vaccinated persons is mild, they are contagious and able to sustain transmission.

Source: Pediatrics. 2006 Jun;117(6):e1070-7.

Primary vaccine failure after 1 dose of varicella vaccine in healthy children.

Universal immunization of young children with 1 dose of varicella vaccine was recommended in the United States in 1995, and it has significantly decreased the incidence of chickenpox. Outbreaks of varicella, however, are reported among vaccinated children. Although vaccine effectiveness has usually been 85%, rates as low as 44% have been observed. Whether this is from primary or secondary vaccine failure-or both-is unclear. We tested serum samples from 148 healthy children immunized against varicella in New York, Tennessee, and California to determine their seroconversion rates, before and after 1 dose of Merck/Oka varicella vaccine. The median age at vaccination was 12.5 months; postvaccination serum samples were obtained on average 4 months later. Serum was tested for antibodies against varicella-zoster virus (VZV) by use of the previously validated sensitive and specific fluorescent antibody to membrane antigen (FAMA) assay. Of 148 healthy child vaccinees, 113 (76%) seroconverted, and 24% had no detectable VZV FAMA antibodies. Our data contrast with reported seroconversion rates of 86%-96% by other VZV antibody tests and suggest that many cases of varicella in immunized children are due to primary vaccine failure. A second dose of varicella vaccine is expected to increase seroconversion rates and vaccine effectiveness.

J Infect Dis. 2008 Apr 1;197(7):944-9. doi: 10.1086/529043.

Varicella outbreak in a highly-vaccinated school population in Beijing, China during the voluntary two-dose era.

Prior to the outbreak, 98.6% of students had received ≥1 dose of varicella vaccine, and most (63.2%) students received two doses. Twenty varicella cases were identified for an overall attack rate of 2.0%. Half of the cases occurred in the classroom of the index case-patient, a two-dose recipient who was not isolated after symptom onset. Breakthrough varicella accounted for 95% of cases (19/20) with attack rates of 14.3% (1/7), 1.6% (6/362) and 2.0% (13/649) among unvaccinated, one-dose, and two-dose students, respectively. Most case-patients (18/20, 90%) had <50 lesions. No difference in clinical presentations was found between one-dose and two-dose recipients with breakthrough varicella.


Moderate two-dose varicella vaccine coverage was insufficient to prevent a varicella outbreak. Two-dose recipients with breakthrough varicella are contagious. High two-dose varicella vaccine coverage and timely isolation of cases may be needed for varicella outbreak prevention in the two-dose era.

Source: Vaccine. 2017 Aug 3;35(34):4368-4373. doi: 10.1016/j.vaccine.2017.06.065. Epub 2017 Jul 3.

Outbreak of varicella in a highly vaccinated preschool population.
‘Index’ Case (Child who started the outbreak) was a Vaccinated Child – They Then Passed it onto 11 Others.

A total of 12 cases occurred during the outbreak, and ten of them (83.3%) had breakthrough varicella. The index case with mild varicella occurred in a child who had been vaccinated four years previously.

Of all the 150 children, 144 (96.0%) had no prior history of varicella disease. Among these children, 135(93.7%) had received single-dose varicella vaccine before the outbreak.

Breakthrough infection with fever in vaccinated person may be as infectious as varicella in unvaccinated persons. High single-dose varicella vaccination coverage is effective in reducing varicella incidence, but not sufficient to prevent outbreak

Int J Infect Dis. 2015 Aug;37:14-8. doi: 10.1016/j.ijid.2015.06.003. Epub 2015 Jun 10.


Add your comment or reply. Your email address will not be published. Required fields are marked *