Epidemic Situation

Year: Week:

NATIONAL WEEKLY INFLUENZA BULLETIN OF THE RUSSIAN FEDERATION

week 47 of 2021 (22.11.21 - 28.11.21)

Summary

Influenza and ARI incidence data. Influenza and other ARI activity increased in Russia in comparison with previous week. The nationwide ILI and ARI morbidity level (87.1 per 10 000 of population) was higher than national baseline (70.0) by 24.4%.

Etiology of ILI & ARI. Among 5136 investigated patients 483 (9.4%) respiratory samples positive for influenza were detected in 32 cities, including 469 cases of influenza A(H3N2) in 32 cities, 13 cases of influenza A unsubtyped in 2 cities and one case of influeza B in one city.

ARVI detections. The overall proportion of respiratory samples tested positive for other ARVI (PIV, ADV, RSV, RhV, CoV, MPV, BoV) was estimated in total as 8.3% (PCR).

In sentinel surveillance system clinical samples from 69 SARI patients were investigated by rRT-PCR, among them 6 (8.7%) cases of influenza recognized including 5 cases of influenza A(H3N2) and one case of iunsubtyped nfluenza A. Among clinical samples from 47 ILI/ARI patients no influenza cases detected. Among 49 SARI patients 9 (18.4%) cases were positive for ARVI, including 2 cases of RSV, 5 cases of RhV and 2 cases of CoV infection. Among 42 ILI/ARI patients 11 (26.2%) cases were positive for ARVI, including one case of RSV, 9 cases of RhV and one case of CoV infection. 18 (26.1%) of 69 SARI patients were positive for coronavirus SARS-CoV-2. Among 44 ILI/ARI patients 4 (19.1%) cases positive for coronavirus SARS-CoV-2 recognized.

Antigenic characterization. Antigenic analysis of 18 influenza (H3N2) viruses in the NIC (Moscow) showed that 12 of them were antigenically related to vaccine strain A/Cambodia/e0826360/20 (H3N2), however 6 strains isolated in Moscow and Yaroslavl were poorly recognized (1/16 of the titer) by rat antiserum to vaccine strain.

Susceptibility to antivirals. All 7 influenza A(H3N2) viruses analysed in the NIC (Moscow) were susceptible to oseltamivir and zanamivir.

Two cases of human infection with avian influenza A(H5) viruses have been reported in Saratov oblast on 46 week. Cases of avian influenza A(H5) in a married couple were diagnosed by rRT-PCR during an investigation of an outbreak of conjunctivitis and avian mortality in a household. The disease was asymptomatic.

COVID-19. Totally 9 703 107 cases and 277 640 deaths associated with COVID-19 were registered in Russia including 33 389 cases and 1221 deaths in last 24 hours (on 12:00 of 02.12.2021). According to the data obtained by NIC in Saint-Petersburg totally 25284 clinical samples were PCR investigated in last week. Among them coronavirus SARS-CoV-2 detected in 5742 (22.7%) cases.

Influenza and ARI morbidity data

Fig. 1. Influenza and ARVI morbidity in 61 cities under surveillance in Russia, seasons 2020/21 and 2021/22
Rates per 10 000 populationFig. 1. Influenza and ARVI morbidity in 61 cities under surveillance in Russia, seasons 2020/21 and 2021/22

Weeks

  • Morbidity 2021/22Morbidity 2021/22
  • Morbidity 2020/21Morbidity 2020/21
  • MEM baseline 2021/22MEM baseline 2021/22

Epidemiological data showed increase of influenza and other ARI activity in Russia in comparison with previous week. The nationwide ILI and ARI morbidity level (87.1 per 10 000 of population) was higher than national baseline (70.0) by 24.4%.

Fig. 2. Comparative data on incidence rate of clinically diagnosed influenza, seasons 2020/21 and 2021/22
Rates per 10 000 populationFig. 2. Comparative data on incidence rate of clinically diagnosed influenza, seasons 2020/21 and 2021/22

Weeks

  • Season 2021/22Season 2021/22
  • Season 2020/21Season 2020/21
  • MEM baselineMEM baseline

Incidence rate of clinically diagnosed influenza increased comparing to previous week and amounted to 0.2 per 10 000 of population, it was 3.3 times higher than pre-epidemic MEM baseline (0.060).

Fig. 3. Comparison of hospitalization rate with clinical diagnosis of influenza, seasons 2020/21 and 2021/22
Rates per 10 000 populationFig. 3. Comparison of hospitalization rate with clinical diagnosis of influenza, seasons 2020/21 and 2021/22

Weeks

  • Season 2021/22Season 2021/22
  • Season 2020/21Season 2020/21
  • MEM baselineMEM baseline

Hospitalization rate of clinically diagnosed influenza increased comparing to previous week and amounted to 0.068 per 10 000 of population, it was 1.7 times higher than pre-epidemic MEM baseline (0.040).

Influenza and ARVI laboratory testing results

Cumulative results of influenza laboratory diagnosis by rRT-PCR were submitted by 46 RBLs and two WHO NICs. According to these data as a result of 5136 patients investigation 483 (9.4%) respiratory samples positive for influenza were detected in 32 cities, including 469 cases of influenza A(H3N2) in 32 cities, 13 cases of influenza A unsubtyped in 2 cities and one case of influenza B in one city.

Antigenic characterization. Antigenic analysis of 18 influenza (H3N2) viruses in the NIC (Moscow) showed that 12 of them were antigenically related to vaccine strain A/Cambodia/e0826360/20 (H3N2), however 6 strains isolated in Moscow and Yaroslavl were poorly recognized (1/16 of the titer) by rat antiserum to vaccine strain.

Susceptibility to antivirals. All 7 influenza A(H3N2) viruses analysed in the NIC (Moscow) were susceptible to oseltamivir and zanamivir.

Two cases of human infection with avian influenza A(H5) viruses have been reported in Saratov oblast on 46 week. Cases of avian influenza A(H5) in a married couple were diagnosed by rRT-PCR during an investigation of an outbreak of conjunctivitis and avian mortality in a household. The disease was asymptomatic.

Fig. 4. Geographic distribution of RT-PCR detected influenza viruses in cities under surveillance in Russia, week 47 of 2021
Fig. 4. Geographic distribution of RT-PCR detected influenza viruses in cities under surveillance in Russia, week 47 of 2021
PCR results
  • No dataNo data
  • No viruses detectedNo viruses detected
  • H1pdm09H1pdm09
  • H3H3
  • H3+H1pdm09H3+H1pdm09
  • BB
  • B+H1pdm09B+H1pdm09
  • B+H3B+H3
  • B+H3+H1pdm09B+H3+H1pdm09
  • A (not subt.)A (not subt.)
  • A (not subt.)+H1pdm09A (not subt.)+H1pdm09
  • A (not subt.)+H3A (not subt.)+H3
  • A (not subt.)+H3+H1pdm09A (not subt.)+H3+H1pdm09
  • A (not subt.)+BA (not subt.)+B
  • A (not subt.)+B+H1pdm09A (not subt.)+B+H1pdm09
  • A (not subt.)+B+H3A (not subt.)+B+H3
  • A (not subt.)+B+H3+H1pdm09A (not subt.)+B+H3+H1pdm09
Fig. 5. Monitoring of influenza viruses detection by RT-PCR in Russia, season 2021/22
Number of positive casesFig. 5. Monitoring of influenza viruses detection by RT-PCR in Russia, season 2021/22% positive

Weeks

  • H1pdm09H1pdm09
  • H3H3
  • BB
  • A (not subt.)A (not subt.)
  • % positive% positive
Fig. 6. Monitoring of ARVI detection by RT-PCR in Russia, season 2021/22
Number of positive casesFig. 6. Monitoring of ARVI detection by RT-PCR in Russia, season 2021/22

Weeks

  • PIVPIV
  • ADVADV
  • RSVRSV
  • RhVRhV
  • CoVCoV
  • MPVMPV
  • BoVBoV

ARVI detections. The overall proportion of respiratory samples tested positive for other ARVI (PIV, ADV, RSV, RhV, CoV, MPV, BoV) estimated as 8.3% of investigated samples by PCR.

Fig. 7. Monitoring of influenza viruses isolation in Russia, season 2021/22
Number of positive casesFig. 7. Monitoring of influenza viruses isolation in Russia, season 2021/22% positive

Weeks

  • H1pdm09H1pdm09
  • H3H3
  • BB
  • % positive% positive

Table 1. Results of influenza and other ARVI detection by RT-PCR in Russia, week 47 of 2021

  Number of  specimens / number of positive cases  % positive
Influenza
Number of specimens tested for influenza 5136 -
Influenza A (not subt.) 13 0,3%
Influenza A(H1)pdm09 0 0,0% 
Influenza A(H3) 469 9,1% 
Influenza B 1 0,02% 
All influenza 483 9,4%
Other ARVI
Number of specimens tested for ARVI 4060  -
PIV 37 0,9%
ADV 33 0,8%
RSV 106 2,6%
RhV 125 3,1%
CoV 10 0,2%
MPV 2 0,05%
BoV 22 0,5%
All ARVI 335 8,3%
SARS-CoV-2 (COVID-19)
Number of specimens tested for SARS-CoV-2 25284 -
SARS-CoV-2 5742 22,7%
Fig. 8. Results of PCR detections of SARS-CoV-2 in Russia
Fig. 8. Results of PCR detections of SARS-CoV-2 in Russia
% positive
  • No dataNo data
  • less then 10%less then 10%
  • 10-20%10-20%
  • 20-30%20-30%
  • 30-40%30-40%
  • 40-50%40-50%
  • 50% and more50% and more

COVID-19. Totally 9 703 107 cases and 277 640 deaths associated with COVID-19 were registered in Russia including 33 389 cases and 1221 deaths in last 24 hours (on 12:00 of 02.12.2021). According to the data obtained by NIC in Saint-Petersburg totally 25284 clinical samples were PCR investigated in last week. Among them coronavirus SARS-CoV-2 detected in 5742 (22.7%) cases.

Table 2. Results of influenza viruses isolation in Russia, week 47 of 2021

  Number of specimens / number of viruses  % isolated viruses
Number of specimens 97 -
Influenza A(H1)pdm09 0 0,0% 
Influenza A(H3) 28 28,9% 
Influenza B 0 0,0% 
All influenza 28 28,9%

Sentinel influenza surveillance

Clinical samples from 69 SARI patients were investigated by rRT-PCR for influenza, among them 6 (8.7%) cases of influenza recognized including 5 cases of influenza A(H3N2) and one case of influenza A unsubtyped. 49 SARI patients were investigated for ARVI by rRT-PCR, among them 9 (18.4%) cases were positive for ARVI, including 2 cases of RSV, 5 cases of RhV and 2 cases of CoV infection. 18 (26.1%) of 69 SARI patients were positive for coronavirus SARS-CoV-2.

Clinical samples from 47 ILI/ARI patients were investigated for influenza and ARVI by rRT-PCR, among them no influenza cases recognized. 11 (26.2%) of 42 ILI/ARI cases were positive for ARVI, including one case of RSV, 9 cases of RhV and one case of CoV infection. 4 (19.1%) of 44 ILI/ARI patients were positive for SARS-CoV2.

Fig. 9. Monitoring of influenza viruses detection by RT-PCR among SARI patients in sentinel hospitals, season 2021/22
Number of positive casesFig. 9.  Monitoring of influenza viruses detection by RT-PCR among SARI patients in sentinel hospitals, season 2021/22% positive

Weeks

  • H1pdm09H1pdm09
  • H3H3
  • BB
  • A (not subt.)A (not subt.)
  • % positive% positive
Fig. 10. Monitoring of influenza viruses detection by RT-PCR among ILI/ARI patients in sentinel polyclinics, season 2021/22
Number of positive casesFig. 10.  Monitoring of influenza viruses detection by RT-PCR among ILI/ARI patients in sentinel polyclinics, season 2021/22% positive

Weeks

  • H1pdm09H1pdm09
  • H3H3
  • BB
  • A (not subt.)A (not subt.)
  • % positive% positive
Fig. 11. Monitoring of ARVI detection by RT-PCR among SARI patients in sentinel hospitals, season 2021/22
Number of positive casesFig. 11.  Monitoring of ARVI detection by RT-PCR among SARI patients in sentinel hospitals, season 2021/22

Weeks

  • PIVPIV
  • ADVADV
  • RSVRSV
  • RhVRhV
  • CoVCoV
  • MPVMPV
  • BoVBoV
Fig. 12. Monitoring of ARVI detection by RT-PCR among ILI/ARI patients in sentinel polyclinics, season 2021/22
Number of positive casesFig. 12.  Monitoring of ARVI detection by RT-PCR among ILI/ARI patients in sentinel polyclinics, season 2021/22

Weeks

  • PIVPIV
  • ADVADV
  • RSVRSV
  • RhVRhV
  • CoVCoV
  • MPVMPV
  • BoVBoV
Download PDF version