Early Evidence of Impact of Monovalent Rotavirus Vaccine in Togo
Early Evidence of Impact of Monovalent Rotavirus Vaccine in Togo
Correspondence: E. Tsolenyanu 1 4
Department of Pediatrics 1 4
National Coordinator for New Vac- cines Surveillance 1 4
Togo (). Clinical Infectious Diseases® 1 4
0 Laboratory Department, Sylvanus Olympio Teaching Hospital of Lomé , Togo
1 The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions , e-mail
2 World Health Organization , Regional Office for Africa, Brazzaville , Congo
3 Department of Paediatrics, Sylvanus Olympio Teaching Hospital of Lomé , Togo
4 Enyonam Tsolenyanu
5 Immunization Focal Point, World Health Organization Country Office , Lomé , Togo
6 Expanded Programme on Immunization, Ministry of Health
7 National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention , Atlanta , Georgia
Togo introduced monovalent rotavirus vaccine starting 19 June 2014. We compared all-cause acute gastroenteritis (AGE) hospitalizations and rotavirus-associated hospitalizations during the prevaccine period (July 2008-June 2014) to 1 year after vaccine introduction (July 2014-June 2015). The proportion of children with AGE who tested positive for rotavirus declined from 53% (645/1223) in prevaccine years to 36% (68/187) in the postvaccine year (P < .01). The decline only occurred in children <1 year of age who were eligible for vaccination and was greatest during the rotavirus season months, supporting that it was associated with vaccine implementation.
Since 2008, sentinel surveillance for AGE and
rotavirusassociated hospitalizations among children <5 years of age
was conducted in 2 sentinel sites in Lomé (Sylvanus Olympio
Teaching Hospital and Be Hospital) using the World Health
Organization’s generic protocol [
]. Children aged <5 years
who were examined at the emergency department due to
AGE (defined as ≥3 liquid or semiliquid stools per 24 hours
lasting <7 days) were included. After written parental consent
was granted, a stool sample was collected. An enzyme-linked
immunosorbent assay (IDEIA Rotavirus, Oxoid) was used for
diagnosis of rotavirus infection according to the manufacturer’s
specifications. Batch testing was conducted monthly at the
sentinel laboratory of Sylvanus Olympio Teaching Hospital.
During the prevaccine period from July 2008 to June 2014, a
total of 1223 children <5 years of age with AGE were enrolled,
of whom 645 (53%) were positive for rotavirus. The proportion
of rotavirus-associated hospitalizations ranged from 41% to
61% in prevaccine years (Figure 1A). For the postvaccine period
from July 2014 to June 2015, 187 children <5 years of age with
AGE were enrolled and 68 (36%) were positive for rotavirus
(mid-P exact <.01). This reflects a reduction of 32% in the
proportion of rotavirus-positive cases during the first postvaccine
year compared with the average of the prevaccine years.
During the prevaccine period, the proportion of
rotavirusassociated hospitalizations among children <1 year of age
hospitalized with AGE ranged from 48% to 62% (Figure 1B); the
mean was 54%. This proportion decreased during the 2014–
2015 period to 31% (mid-P exact <.01), representing a decline
of 43% from the mean in prevaccine years. Among children 1–4
years of age, the proportion of rotavirus-associated
hospitalizations ranged from 30% to 60% (Figure 1C); the mean was 46%.
This proportion was 42% in 2014–2015, and the change during
the pre- and postvaccine periods was not statistically significant
(mid-P exact = .21).
The majority of AGE cases (56%) were observed during the
period from December to March. The proportion of
rotavirus-associated hospitalizations was also high (69%) during these months
(Figure 2A). Again, reductions during these peak rotavirus season
months during the first postvaccine season were most marked
among infants aged 0–11 months (Figure 2B and 2C), whereas
declines were not evident in 1- to 4-year-old children.
The first dose of RV1 reported coverage increased from 75%
in January 2015 to 100% in June 2015 in vaccine age-eligible
children. The second dose coverage also increased from 71%
to 85% during this period. RV1 vaccine coverage rates in
older children were negligible.
We report early evidence of the impact of RV1 in Togo, with
rapid and marked reductions in the proportion of AGE
hospitalizations associated with rotavirus in the first year after vaccine
implementation. The fact that the decline in the postvaccine
period was limited to children <1 year of age—who were age
eligible for vaccination—and was not seen in unvaccinated
children 1–4 years of age supports that it was associated with
vaccine implementation, as does the finding that the decline
primarily occurred during the months with peak rotavirus activity
(December–March). Despite the short duration of post–vaccine
introduction surveillance and the small number of children
included, our findings support continued vaccination of Togolese
children against rotavirus; as vaccine coverage increases and
extends to older children, we anticipate even greater declines that
should be monitored through continued surveillance.
Acknowledgments. The authors acknowledge the Ministry of Health
and national Expanded Programme for Immunization in Togo for the
guidance and leadership in implementing the new-vaccines surveillance.
Disclaimer. The findings and conclusions in this report are those of the
authors and do not necessarily represent the official position of the Centers
for Disease Control and Prevention (CDC) or the World Health
Organization (WHO). The views expressed by the authors do not necessarily reflect
the views of PATH, the CDC Foundation, the Bill and Melinda Gates
Foundation, or GAVI, the Vaccine Alliance.
Financial support. Financial support for this project was provided by
Gavi, the Vaccine Alliance, supporting new-vaccines surveillance to WHO
Regional Office for Africa.
Supplement sponsorship. This article appears as part of the supplement
“Health Benefits of Rotavirus Vaccination in Developing Countries,”
sponsored by PATH and the CDC Foundation through grants from the Bill and
Melinda Gates Foundation and GAVI, the Vaccine Alliance.
Potential conflicts of interest. All authors: No reported conflicts. All
authors have submitted the ICMJE Form for Disclosure of Potential
Conflicts of Interest. Conflicts that the editors consider relevant to the
content of the manuscript have been disclosed.
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