WEEKLY BULLETIN ON OUTBREAKS
AND OTHER EMERGENCIES
Week 31: 25 - 31 July 2022
Data as reported by: 17:00; 31 July 2022
...
Wild Poliovirus Mozambique
4 cases
0 Deaths
0% CFR
EVENT DESCRIPTION
Following the detection of the first case of wild poliovirus type
1 (WPV1) on 18 May 2022 in north-eastern Tete province of
Mozambique, three new cases have been reported in the country.
The first case is a 1-year and 7 months-old male, resident of
Nkondezi village, located approximately 110 kilometres from
Moatize city, and 30 kilometres to the nearest health facility with
very difficult road network especially during the rainy season. The
case was notified on 3 June 2022 with paralysis onset date of 25
May 2022. Subsequently, timely stool samples were collected on
6 and 7 June 2022 respectively, and sent to regional laboratory
for analysis. The child had no history of any routine vaccination
doses. No travel history was nor contact with any child or person
with paralysis was reported.
The second case is a 7 months-old-male, resident of chikhona
village, who had received 2OPV doses with no IPV. The case
was notified on 26 May 2022 with paralysis onset date of 20
May 2022. Stool samples were collected on 5 and 6 June 2022
respectively, and sent to regional laboratory. The family reports
receiving visitors from Tete district a month before onset of
paralysis. Notably, the child was taken to Tete province seeking
better medical assistance after being notified and investigated as
AFP case.
The third case; a 3-year and 8 months-old female, from Chinhanje
village. Parents to the child report no history of any vaccination.
The case was notified on 13 June 2022 with paralysis onset date
of 10 June 2022. Stool samples were collected on 14 and 15 June
2022 respectively, and sent to regional laboratory for analysis.
All the samples were shipped to laboratories at the National
Institute of Communicable Disease in South Africa and the
Centers for Disease Control and Prevention in the United States
for further testing and sequencing. Test results received on 18
July 2022, confirmed the presence of WPV1 in the stool samples.
Genetic analysis further indicates that there are clearly at least
two transmission chains that co-evolved after introduction of
the virus in Tete province in Mozambique. While it is difficult
to speculate, distribution of WPV1 and their genetic linkage
suggests that missed transmission in bordering areas around
Mozambique-Zimbabwe-Zambia cannot be ruled out.
In 2022, Tete province has registered acceptable AFP indicators
/ Polio surveillance performance in nearly all its districts 14/15
(93.7%) noting improvement as compared with the previous
year (2021). However, slight improvement in proportion of cases
with adequate stool samples was registered in the same year as
compared to the previous year -2021.
PUBLIC HEALTH ACTIONS
The Ministry of Health is coordinating the response with
technical and operational support from partners of the Global
Polio Eradication Initiative (GPEI) including the African Rapid
Response Team and the Global Polio Laboratory Network.
A rapid response team involving staff from the national
and sub-national levels as well as GPEI experts have been
deployed to conduct a detailed investigation, assess the risk
associated with this event, and implement targeted response
activities.
Surveillance including active case finding is being enhanced
in the affected district.
Two rounds of bivalent OPV campaigns have already been
implemented, the most recent in April, with more than 4.2
million children vaccinated in Mozambique. At the same time,
the response to the cVDPV2 outbreak is also ongoing.
SITUATION INTERPRETATION
Mozambique has implemented three immunization rounds
using bOPV since the detection of the first case from March.
Assessments of these rounds show gradual improvements in
quality, round to round, though quality remains suboptimal in
Tete province.
With detection of more WPVI cases, cross-border collaboration
for enhanced surveillance and high-quality public health response
including vaccination remains critical in protecting countries of
the sub-region and preventing a potential resurgence of the polio
epidemic in Africa. WHO advises countries to implement highquality
surveillance, routine vaccination, and response activities
to prevent the potential resurgence and spread of the poliovirus.
https://apps.who.int/iris/bitstream/handle/10665/361243/OEW31-2531072022.pdf