On 2016 Mar 11, Gary Goldman commented:

Jumaan et al [1], only consider the mean herpes zoster (HZ) incidence rate for each age category. However, those age categories consisting of children and adolescents (<20 years-old) comprise three widely different cohorts: (1) those still susceptible to varicella and never vaccinated (exhibiting HZ incidence of 0 cases/100,000 person-years); (2) those that have had a prior history of natural (wild-type) varicella who exhibit increasing HZ incidence rates (up to a maximum HZ incidence of 500 cases/100,000 p-y when exogenous boosting becomes rare); and (3) those vaccinated who exhibit HZ incidence rates less than typical for their age category since they have been recently boosted.

Ironically, while utilizing a single mean for a bimodal (or trimodal) distribution and claiming that Goldman has made methodological errors, Civen et al in a study published in 2009 [2], having some of the same authors as the Scientific Commentary [1], utilized methodology similar to that of Goldman [3,4], and reported nearly the same HZ incidence rates stratified by vaccine status and prior history of natural varicella. [5]

The uncorrected 2000-2006 cumulative HZ incidence rates reported by Civen et al [2] and 2000-2003 cumulative HZ incidence rates reported by Goldman [6] among those vaccinated, aged 1- to 9-years are 19 (95% C.I., 15-25)/100,000 p-y and 14 (95% C.I., 9-21)/100,000 p-y, respectively. Correcting for 50% underreporting of HZ cases, Goldman estimates an ascertainment-corrected HZ incidence rate of 28 cases/100,000 p-y which is remarkably similar to the HZ incidence rate of 27.4 (95% C.I., 22.7-32.7)/100,000 p-y reported by Tseng et al based on 172,163 vaccinated children with overall follow-up of 446,027 p-y among children <=12 years of age. [7]

The uncorrected HZ incidence rates reported by Civen et al [2] and Goldman [6] among those with a history of natural varicella, aged 1- to 9-years are 230 (95% C.I., 193-295)/100,000 p-y and 221 (95% C.I., 180-273)/100,000 p-y, respectively. Correcting for 50% under-reporting, Goldman reports an ascertainment-corrected HZ incidence rate of 446/100,000 p-y, a figure approaching that characteristic of older adults.

Finally, the uncorrected HZ incidence rates reported by Civen et al [2] and Goldman [6] among those with a history of natural varicella, aged 10- to 19-years are 69 (95% C.I., 61-77)/100,000 p-y and 61 (95% C.I., 51-72)/100,000 p-y, respectively. The ascertainment-corrected HZ incidence rate of 162/100,000 p-y demonstrates a slightly elevated rate for this age category (compared to that of Hope-Simpson and the rate prior to universal varicella vaccination).

HZ incidence rates that are ascertainment-corrected, as reported by Goldman [6], can be appropriately compared to other HZ incidence rates that are presented in other studies that similarly reflect high case ascertainment. [8] The methodology recommended by Jumaan et al [2] presents a single mean for a bimodal distribution which does not account for the widely differing HZ incidence rates between cohorts that have been administered varicella vaccine and those having a prior history of natural varicella. Six to seven years following the implementation of the universal varicella vaccination program, Goldman [3,4] showed the significant effect that a severe loss in exogenous boosting had on increasing HZ incidence in children with a prior history of natural varicella--rates approaching those characteristic of older adults. As early as 1965, Dr. Hope-Simpson anticipated this outcome with his hypothesis, “The peculiar age distribution of zoster may in part reflect the frequency with which the different age groups encounter cases of varicella and, because of the ensuing boost to their antibody production, have their attacks of zoster postponed.” [9]

References:

[1] Jumaan A, Schmid DS, Gargiullo P, Seward J. Scientific Commentary. Vaccine 2004. 22(25-26):3228-3331 author reply 3232-3236. Jumaan A, 2004

[2] Civen R, Chaves S, Jumaan A, Wu H, Mascola L, Garguiullo P, et al. The incidence and clinical characteristics of herpes zoster among children and adolescents after implementation of varicella vaccination. Pediatr Infect Dis J 2009;28(November(11)):954-959. Civen R, 2009

[3] Goldman GS. Incidence of herpes zoster among children and adolescents in a community with moderate varicella vaccination coverage. Vaccine 2003 Oct 1;21(27-30):4243-4249. Goldman GS, 2003

[4] Goldman GS. Varicella susceptibility and incidence of herpes zoster among children and adolescents in a community under active surveillance. Vaccine 2003 Oct 1;21(27-30):4238-4242. Goldman GS, 2003

[5] Goldman GS, King PG. Review of the United States universal varicella vaccination program: Herpes zoster incidence rates, cost-effectiveness, and vaccine efficacy based primarily on the Antelope Valley Varicella Active Surveillance Project data. Vaccine 2013 Mar 25;31(13):1680-1694. Goldman GS, 2013

[6] Goldman GS. Universal varicella vaccination: efficacy trends and effect on herpes zoster. Int J Toxicol 2005;24(July/August(4)):205-213. Goldman GS, 2005

[7] Tseng HF, Smith N, Marcy SM, Sy LS, Jacobsen SJ. Incidence of herpes zoster among children vaccinated with varicella vaccine in a prepaid health-care plan in the United States, 2002-2008. Pediatr Infec Dis J, 2009;28(December(12));1069-1072. Tseng HF, 2009

[8] Hook EB, Regal RR. The value of capture-recapture methods even for apparent exhaustive surveys: the need for adjustment for source of ascertainment intersection in attempted complete prevalence studies. Am J Epidemiol 1992; 135:1060-1067. Hook EB, 1992

[9] Hope-Simpson RE. The nature of herpes zoster: a long-term study and a new hypothesis. Proc R Soc Med. 1965 Jan; 58(1): 9–20. HOPE-SIMPSON RE, 1965

On 2016 Mar 01, Gary Goldman commented:

None

On 2016 Mar 01, Gary Goldman commented:

None

On 2016 Mar 11, Gary Goldman commented:

Jumaan et al [1], only consider the mean herpes zoster (HZ) incidence rate for each age category. However, those age categories consisting of children and adolescents (<20 years-old) comprise three widely different cohorts: (1) those still susceptible to varicella and never vaccinated (exhibiting HZ incidence of 0 cases/100,000 person-years); (2) those that have had a prior history of natural (wild-type) varicella who exhibit increasing HZ incidence rates (up to a maximum HZ incidence of 500 cases/100,000 p-y when exogenous boosting becomes rare); and (3) those vaccinated who exhibit HZ incidence rates less than typical for their age category since they have been recently boosted.

Ironically, while utilizing a single mean for a bimodal (or trimodal) distribution and claiming that Goldman has made methodological errors, Civen et al in a study published in 2009 [2], having some of the same authors as the Scientific Commentary [1], utilized methodology similar to that of Goldman [3,4], and reported nearly the same HZ incidence rates stratified by vaccine status and prior history of natural varicella. [5]

The uncorrected 2000-2006 cumulative HZ incidence rates reported by Civen et al [2] and 2000-2003 cumulative HZ incidence rates reported by Goldman [6] among those vaccinated, aged 1- to 9-years are 19 (95% C.I., 15-25)/100,000 p-y and 14 (95% C.I., 9-21)/100,000 p-y, respectively. Correcting for 50% underreporting of HZ cases, Goldman estimates an ascertainment-corrected HZ incidence rate of 28 cases/100,000 p-y which is remarkably similar to the HZ incidence rate of 27.4 (95% C.I., 22.7-32.7)/100,000 p-y reported by Tseng et al based on 172,163 vaccinated children with overall follow-up of 446,027 p-y among children <=12 years of age. [7]

The uncorrected HZ incidence rates reported by Civen et al [2] and Goldman [6] among those with a history of natural varicella, aged 1- to 9-years are 230 (95% C.I., 193-295)/100,000 p-y and 221 (95% C.I., 180-273)/100,000 p-y, respectively. Correcting for 50% under-reporting, Goldman reports an ascertainment-corrected HZ incidence rate of 446/100,000 p-y, a figure approaching that characteristic of older adults.

Finally, the uncorrected HZ incidence rates reported by Civen et al [2] and Goldman [6] among those with a history of natural varicella, aged 10- to 19-years are 69 (95% C.I., 61-77)/100,000 p-y and 61 (95% C.I., 51-72)/100,000 p-y, respectively. The ascertainment-corrected HZ incidence rate of 162/100,000 p-y demonstrates a slightly elevated rate for this age category (compared to that of Hope-Simpson and the rate prior to universal varicella vaccination).

HZ incidence rates that are ascertainment-corrected, as reported by Goldman [6], can be appropriately compared to other HZ incidence rates that are presented in other studies that similarly reflect high case ascertainment. [8] The methodology recommended by Jumaan et al [2] presents a single mean for a bimodal distribution which does not account for the widely differing HZ incidence rates between cohorts that have been administered varicella vaccine and those having a prior history of natural varicella. Six to seven years following the implementation of the universal varicella vaccination program, Goldman [3,4] showed the significant effect that a severe loss in exogenous boosting had on increasing HZ incidence in children with a prior history of natural varicella--rates approaching those characteristic of older adults. As early as 1965, Dr. Hope-Simpson anticipated this outcome with his hypothesis, “The peculiar age distribution of zoster may in part reflect the frequency with which the different age groups encounter cases of varicella and, because of the ensuing boost to their antibody production, have their attacks of zoster postponed.” [9]

References:

[1] Jumaan A, Schmid DS, Gargiullo P, Seward J. Scientific Commentary. Vaccine 2004. 22(25-26):3228-3331 author reply 3232-3236. Jumaan A, 2004

[2] Civen R, Chaves S, Jumaan A, Wu H, Mascola L, Garguiullo P, et al. The incidence and clinical characteristics of herpes zoster among children and adolescents after implementation of varicella vaccination. Pediatr Infect Dis J 2009;28(November(11)):954-959. Civen R, 2009

[3] Goldman GS. Incidence of herpes zoster among children and adolescents in a community with moderate varicella vaccination coverage. Vaccine 2003 Oct 1;21(27-30):4243-4249. Goldman GS, 2003

[4] Goldman GS. Varicella susceptibility and incidence of herpes zoster among children and adolescents in a community under active surveillance. Vaccine 2003 Oct 1;21(27-30):4238-4242. Goldman GS, 2003

[5] Goldman GS, King PG. Review of the United States universal varicella vaccination program: Herpes zoster incidence rates, cost-effectiveness, and vaccine efficacy based primarily on the Antelope Valley Varicella Active Surveillance Project data. Vaccine 2013 Mar 25;31(13):1680-1694. Goldman GS, 2013

[6] Goldman GS. Universal varicella vaccination: efficacy trends and effect on herpes zoster. Int J Toxicol 2005;24(July/August(4)):205-213. Goldman GS, 2005

[7] Tseng HF, Smith N, Marcy SM, Sy LS, Jacobsen SJ. Incidence of herpes zoster among children vaccinated with varicella vaccine in a prepaid health-care plan in the United States, 2002-2008. Pediatr Infec Dis J, 2009;28(December(12));1069-1072. Tseng HF, 2009

[8] Hook EB, Regal RR. The value of capture-recapture methods even for apparent exhaustive surveys: the need for adjustment for source of ascertainment intersection in attempted complete prevalence studies. Am J Epidemiol 1992; 135:1060-1067. Hook EB, 1992

[9] Hope-Simpson RE. The nature of herpes zoster: a long-term study and a new hypothesis. Proc R Soc Med. 1965 Jan; 58(1): 9–20. HOPE-SIMPSON RE, 1965