The incidence of herpes zoster in China: A meta-analysis and evidence quality assessment.

This review aimed to estimate the disease burden of herpes zoster (HZ) in China and explore the application of the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) approach in studies of disease burden. We searched for the literature of observational studies analyzing HZ incidence in populations of all ages in China. Meta-analysis models were constructed to calculate the pooled incidence of HZ and pooled risks of postherpetic neuralgia (PHN), HZ recurrence, and hospitalization. Subgroup analysis was performed according to gender, age, and quality assessment score. The quality of evidence for incidence was rated using the GRADE system. Twelve studies with a total of 25,928,408 participants were included in this review. The pooled incidence for all ages was 4.28/1000 person years (95% CI 1.22-7.35). It increased with the increasing in age especially for individuals aged ≥60 y, which was 11.69/1000 person years (95% CI 6.56-16.81). The pooled risks of PHN, recurrence, and hospitalization were 12.6% (95% CI 10.1-15.1), 9.7% (95% CI 3.2-16.2), and 6.0/100,000 population (95% CI 2.3-14.2), respectively. The quality of the evidence assessment of the pooled incidence by the GRADE for all ages was 'low'; however, it was 'moderate' for the ≥60 yold subgroup. HZ is a serious public health problem in China and is more significant in individuals older than 60 y. Therefore, an immunization strategy for the zoster vaccine should be considered. The evidence quality assessment by the GRADE approach indicated that we had more confidence in the estimation of aged population.

Two-dose varicella vaccine effectiveness in China: a meta-analysis and evidence quality assessment.

BACKGROUND: The objectives of this review were to evaluate the vaccine effectiveness (VE) of the two-dose varicella vaccine for healthy children in China and explore the application of the approach of Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) in observational studies on VE. METHODS: We searched for observational studies on two-dose varicella VE for children in China aged 1-12 years that were published from 1997 to 2019, and assessed the quality of each study using the Newcastle Ottawa Scale (NOS). We used meta-analysis models to obtain the pooled two-dose VE, and the studies were divided into subgroups and analysed according to whether or not it was an outbreak investigation and its NOS score. The quality of evidence of VEs were rated by approach of the GRADE system. RESULTS: A total of 12 studies and 87,196 individuals were included. The pooled two-dose VE was 90% (95% confidence interval [CI]: 69-97%). The VE of outbreak studies (87% [95% CI: 76-93%]) was lower than non-outbreak studies (99% [95% CI: 98-99%]). There was no significant difference in VEs by different NOS quality. The quality of the evidence assessment of pooled two-dose VE was "low", which was rated down by one category in limitations and publication bias respectively and rated up by two category in large effect. The quality of evidence assessment in subgroup of NOS score ≥ 7 was "moderate". CONCLUSIONS: The VE of two-dose varicella vaccine is relatively high in preventing varicella, and is recommended for countries which need further control for varicella. However, higher quality evidence is needed as a supplement for stronger recommendations. The approach of GRADE could be applied for rating the quality of evidence in observational study.

Seroepidemiology of pertussis in China: A population-based, cross-sectional study.

BACKGROUND: Despite high pertussis vaccination coverage and significant decrease of pertussis since the adoption of the Expanded Programme on Immunization (1978), increased pertussis incidence has been reported in China from 2013 to 2017. This study aimed at evaluating the immune response to pertussis among vaccinated children and beyond in China. METHODS: The study recruited 2 144 healthy subjects. Serum IgG antibodies against pertussis toxin (anti-PT IgG) were measured by ELISA. Anti-PT IgG concentration (GMC), seropositivity rate (GMC ≥ 40 IU/ml), and recent infection rate (GMC > 100 IU/ml) were calculated. Participants ≤ 2 years-old were further stratified by vaccination schedule intervals and participants ≤ 6 years-old by vaccine used (Domestic DTaP or DTaP-IPV//PRP ~ T (Pentaxim, SP)). RESULTS: Among 0-6-year-olds, the anti-PT IgG GMC was 5.99 IU/ml (95%CI 5.39-6.67). The GMC increased in accordance with the primary vaccination series (4-6 months) and the toddler booster (18-23 months), and continuously declined thereafter to its nadir at 6 years-old [3.72 IU/ml (95%CI 2.91-4.77)]. GMCs were markedly higher in those vaccinated with DTaP-IPV/PRP ~ T compared to DTaP. In individuals > 6 years-old, the GMC was 5.67 IU/ml (95%CI 5.36-6.00), the seropositivity rate was 6.7% (95%CI 5.5-7.9) and the recent infection rate was 1.2% (95%CI 0.7-1.7). The seropositivity rates increased from 6 years-old and peaked at 9 years-old (10.3% [95%CI 0.7-19.8]). CONCLUSIONS: Vaccination against pertussis increases anti-PT IgG, but wanes over time. The sero-estimated infection rates increase from school age and peak at about 9 years-old. These results support the addition of a booster of pertussis vaccine at preschool age.

Seroprevalence of poliovirus antibodies before and after polio vaccine switch in 2012 and 2017 in Beijing.

In 2000, China was declared polio-free. However, in 2018, wild poliovirus (WPV) was still endemic in two of its neighboring countries, making WPV importation and outbreak alarming possibilities. This study documents the seroprevalence of poliovirus antibodies before and after the polio vaccine switch in 2012 and 2017 in Beijing. Cross-sectional population-based serologic surveys were conducted in 2012 and 2017 in Beijing. The study subjects were selected from 10 different age groups (<1, 1-4, 5-9, 10-14, 15-19, 20-24, 25-29, 30-34, 35-39, and ≥40 y) using a multi-stage-stratified sampling method. Neutralizing antibody titers against poliovirus serotypes 1 (P1), 2 (P2), and 3 (P3) were assayed by World Health Organization standards. The seropositive rates (SR) and geometric mean titer (GMT) of the neutralizing antibodies were 91.71% and 1:130.26, respectively, for P1, 94.09% and 1:113.39, respectively, for P2, and 88.78% and 1:79.65, respectively, for P3 before the switch in 2012, and 87.78% and 1:108.93, respectively, for P1, and 81.67% and 1:70.56, respectively, for P3 after the switch in 2017, with a statistically significant difference for P1 and P3 between 2012 and 2017. The neutralizing antibodies for all poliovirus serotypes differed among different age and vaccination groups in both 2012 and 2017. After switching polio vaccines twice in 2014 and 2016, the P1 and P3 polio antibody levels were lower in 2017 than in 2012. The P2 antibody levels were determined from the first dose of IPV. The seroprevalence of poliovirus antibodies after adjustment of the immunization schedule of the polio vaccine on January 1, 2020, must be further monitored.

Outbreak of measles among persons with secondary vaccine failure, China, 2018.

Although the incidence of measles has been dramatically reduced by the highly effective measles vaccine, cases of measles and outbreaks continue to occur in vaccinated population because of immunization failure. We report on an outbreak in which two cases had previous evidence of measles immunity and then one of them transmitted measles infection to an unvaccinated contact. The cases and contacts exposed during the outbreak were investigated. Clinical information and epidemiological information were obtained. Serum samples were collected for measles-specific immunoglobulin M (IgM), immunoglobulin G (IgG) and IgG avidity. Throat swabs were obtained to test for measles virus RNA. Two measles cases (case 1 and case 2) who have received one dose of MCV in past 5 years, and both working at a hospital in Beijing, occurred in 18th and 20nd of January, respectively. Out of the 102 contacts, one additional case (case 3) who had a close, long-term co-exposure with case 1 was reported subsequently. No additional cases of measles occurred among 15 contacts of case 3. The index case was not ascertained through the outbreak review. All three cases had laboratory confirmation of measles infection. Both case 1 and case 2 had high-avidity IgG antibody characteristic of a secondary immune response and developed a modified clinical presentation. This report confirms that a vaccinated individual with documented secondary vaccine failure (SVF) could transmit measles and is the second report since a New York City outbreak (the first report in China). The outbreak represented a series of rare events, so we can conclude that the SVF individuals in the transmission chain of measles are unlikely to threaten measles elimination. The importance of the herd immunity in preventing transmission and sensitive surveillance activities in case of misdiagnosis is emphasized.

Seroepidemiology of measles in Beijing, China: a cross-sectional study.

The aim of this study was to assess the seroprevalence of measles and identify the high risk of measles infection in the general population of Beijing. A total of 2144 subjects aged 0-76 years old were selected using a multi-stage stratified sampling method. Socio-demographic characteristics, vaccination history, and disease history of measles were collected by questionnaire. Serum samples were tested for measles-specific IgG by using commercial ELISA kits. The overall seropositivity rate of measles was 79.80% (95% CI 78.1-81.5%) and standardized seropositivity rate was 84.61% (95% CI 84.12-87.10%), with the median concentration of 773.40IU/L. The area of Beijing with the highest seroprevalence was the central area [81.79% (95% CI 80.16-83.42%) and 855.84IU/L]. There were no significant differences in seropositivity rates of different genders (P = 0.074), history of measles infection (P = 0.421) and registered population (P = 0.598). The 1-4 age group had the highest seropositivity rate [94.06%(95% CI 93.06-95.06%)] and children below the age of 1 (0-12 months) had the lowest seropositivity rate [34.42% (95% CI 32.41-36.43%)]. The 30-34 and 35-39 age groups were relatively lower with 72.90% (95% CI 71.02-74.78%) and 74.65% (95% CI 72.81-76.49%) respectively. Seropositivity rates changed along with the incidence rates of measles periodically by years. As shown in the present study, the seroprevalence of measles antibody in Beijing have not yet met the threshold required to achieve measles elimination and therefore the risk of an epidemic of measles will be existing. Appropriate targeted immunization strategies and measures should be considered and carried out.

Knowledge, attitudes, and practices regarding hepatitis B vaccination among hospital-based doctors and nurses in China: Results of a multi-site survey.

BACKGROUND: Hepatitis B virus (HBV) can cause chronic HBV infection, which may lead to advanced cirrhosis and liver cancer. Healthcare workers (HCWs) are at risk HBV infection as an occupational hazard. Hepatitis B vaccination of HCWs is recommended by WHO, but the status of hepatitis B vaccination among HCWs in China is seldom reported. METHODOLOGY: We conducted a cross-sectional study in 22 hospitals of 3 developed cities in China. We interviewed managers in infectious diseases and occupational health departments, and at least 40 HCWs per hospital. RESULTS: We interviewed 929 HCWs; 80.8% were vaccinated against hepatitis B and 96.7% were willing to be vaccinated; 38.2% of HCWs reported having at least one needle stick or sharps injury. Three hospitals provide free hepatitis B vaccination for HCWs; hospitals with a hepatitis B vaccination policy, more HCWs reported being vaccinated (91.7% vs 79.0%, P < 0.001). HCWs in high risk departments (P = 0.011), with more knowledge of hepatitis B vaccine (P < 0.001), and with fewer working years (P = 0.002) were more likely to be vaccinated against HBV. Infectious diseases and occupational health managers had positive attitudes towards hepatitis B vaccination. CONCLUSIONS: Hepatitis B vaccination was well accepted among HCWs. Hospital provision of free vaccine, greater HCW knowledge of HBV, and working in higher-risk settings were associated with being vaccinated. A national policy of offering hepatitis B vaccine to HCWs should be considered in China. Provision of free hepatitis B vaccine for HBsAb negative HCWs may be acceptable. Education about HBV and hepatitis B vaccine may help promote policy implementation.

Immunogenicity and persistence from different 3-dose schedules of live and inactivated polio vaccines in Chinese infants.

BACKGROUND: OPV is the only poliovirus vaccine used in the China EPI system, although IPV is available in the private market. We compared immunigencity and persistence among different schedules of IPV and OPV. METHODS: 536 Chinese infants were enrolled into 4 groups receiving different schedules administered at 2, 3, and 4 months of age: IPV-OPV-OPV, IPV-IPV-OPV, IPV-IPV-IPV, and OPV-OPV-OPV. The I-I-I group received an 18-month IPV booster dose. Blood samples were collected before the first dose, after the third dose, and at 18 months for all groups, and also after the booster dose for the I-I-I group. Polio neutralizing antibody titers were assessed, and seroprotection rates were calculated after primary immunization and at 18 months of age. RESULTS: Before the first dose, GMTs of the 4 groups ranged from 2.96 to 6.89, and seroprotection rates ranged from 17.6% to 54.3%. After 3 doses, the GMT of the I-O-O and I-I-O groups ranged from 901.09 to 1,110.12, and the GMT of the I-I-I group range was 212.02 to 537.52, significantly lower than for the 2 sequential schedules (P<0.001). Seroprotection rates were 98.1% to 100%, with no significant differences among groups. At 18 months of age, the GMTs declined to a range of 527.00 to 683.44 in the I-O-O and I-I-O groups, and declined to 150.04 to 239.89 in the I-I-I group, significantly lower than for the other 3 groups (P<0.001). CONCLUSIONS: The sequential schedules achieved high GMTs and seroprotection. The IPV-only schedule achieved high seroprotection but with lower GMTs. Sequential schedules are suitable for China. With the 2 sequential schedules, GMTs remained high at 18 months of age and were not inferior to the OPV-only schedule. Thus, with a sequential schedule, the booster dose could be given at 4 years of age, the same age as the current OPV booster dose.

[Changes of epidemiological characteristics of measles in Beijing before and after supplementary immunization campaigns of measles vaccine in 2010].

OBJECTIVE: To investigate the changes of epidemiological characteristics of measles in Beijing before and after Supplementary Immunization Campaigns (SIA) (2007-2010 vs 2011-2014) of measles-containing vaccine (MCV) among children aged between 8 months and 14 years in 2010. METHODS: Descriptive epidemiological analysis was conducted on surveillance data of measles cases (clinical cases and laboratory confirmed cases), with the occurrence during 2007-2014, and of outbreaks, with the occurrence during 2009-2014, from National Notifiable Disease Reporting System. MapInfo geographic information system (Version 8.5) was used to illustrate the distribution of measles incidence by district. Annual measles incidence was classified into 5 groups at the same intervals between the upper and lower limits to analyze the morbidity of the different areas. RESULTS: In total, 7 722 and 3 132 measles cases were reported during 2007-2010 and 2011-2014, with the annual incidence of 11.59 and 3.84 cases per 100 000 population, respectively. Comparing with the results during 2007-2010, total number of measles cases and average annual incidence during 2011-2014 were decreased by 59.4%, and 66.9%, respectively. Among measles cases during 2011-2014, percentage of cases aged 15 years or above were 57.7%(56/97), 62.0%(49/79), 65.5%(370/565), and 71.4% (1 707/2 391), respectively, which increased by years. During 2007-2010, the highest risk age for adults was 20-34, while 2011-2014, 5 years older: 25-39. During 2009-2010, 2011-2012, and 2013-2014, 50.3% (447/889), 30.3% (10/33), and 57.8% (201/348), respectively, of measles cases aged 8-17 months were unvaccinated by MCV. Percentages of measles cases aged 0-7 months, 8 months-14 years, 15-39 years and 40 years or above during 2013-2014, who visited hospitals 7-21 days before disease onset, were 59.8% (238/398), 49.3% (237/481), 32.2% (529/1641), and 37.6% (164/436), respectively. A total of 11 nosocomial measles outbreaks occurred during 2013-2014, which was much higher than that during 2009-2010 (2 nosocomial outbreaks). And universities accounted for the majority of outbreak settings of schools (3/4). All 11 outbreaks among grouped employees during 2009-2012 occurred in factories, restaurants, or large shopping centers, while the largest proportion (6/16) of that kind of outbreaks during 2013-2014 occurred in office buildings. CONCLUSIONS: SIA of MCV in 2010 effectively decreased measles transmission in Beijing. But routine immunization of MCV still needed to be improved. The issue of adult measles has been a prominent problem. Hospitals, office buildings and universities were the focus of prevention of measles transmission.

[Immunogenicity and safety of a booster dose of inactivated polio vaccine].

OBJECTIVE: To evaluate the immunogenicity and safety of a boost dose of inactivated polio vaccine (IPV) among children aged 18 months who had been administered with primary doses of IPV. METHODS: Form 2011 to 2012, a total of 97 children were enrolled in the present study who were vaccinated with IPV at 2, 3, 4 months of age and boosted with the same vaccine at 18 months of age. Anti-poliovirus neutralizing antibody titers in serum were measured before and after booster vaccination, geometric mean titers (GMT) and seroprotection rate were calculated. Adverse events occurring within 30 days after booster vaccination were observed, including pain, redness/swelling and induration at the injection site, fever, vomit, abnormal crying, drowsiness, loss of appetite, irritability, and all other physical discomfort and related medications were also recorded. A descriptive analysis was performed for the safety assessment. RESULTS: Immunogenicity was assessed in 84 subjects. The pre-booster seropositivity rates of neutralizing antibody against poliovirus type 1, 2, 3 before booster were all 100% (84/84) and the corresponding GMT (95% CI) was 1: 148.5 (116.49-189.29) , 1: 237.68 (178.39-316.67) and 1: 231.87 (181.27-296.58) , respectively. The seropositivity rates of neutralizing antibody against the three types of poliovirus after booster were all 100% (84/84) and the corresponding GMT (95% CI) was 1: 1612.14 (1470.57-1767.34) , 1: 1854.92 (1715.83-2005.29) and 1: 1625.50 (1452.12-1819.58) , respectively. The pre-booster titer of neutralizing antibody against poliovirus type 1, 2, 3 mainly ranged 1: 128-1: 512, which accounted for 65% (55/84) , 55% (46/84) , 74% (62/84) in each type. After the booster immunization, titers of neutralizing antibody against type 1, 2, 3 were increased as subjects with titer ≥ 1: 1024 accounted for 94% (78/84) , 95% (80/84) , 92% (77/84) , respectively.Safety was evaluated in 96 subjects, of which 16 subjects reported adverse events with the rate of 17%. The observed local events were mainly tenderness 3% (3/96) , redness/swelling and induration were not reported. The systemic adverse events included loss of appetite (8%, 8/96) , irritability (8%, 8/96) , fever (7%, 7/96) , abnormal crying (6%, 6/96) , drowsiness (6%, 6/96) and vomit (1%, 1/96) . All reported adverse events were mild or moderate. All of the local events occurred in the day of vaccination and lasted for 1-2 days, while systemic events almost developed within 2 days after vaccination and last less than 3 days. CONCLUSION: IPV booster dose has good immunogenicity and safety profile, which provides effective protection against poliovirus.

[Safety of different sequential immunization schedules of inactivated poliovirus vaccine and oral poliovirus vaccine primary vaccination].

OBJECTIVE: To evaluate safety of different sequential immunization schedules of inactivated poliovirus vaccine (IPV) and oral poliovirus vaccine (OPV) primary vaccination. METHODS: Infants of 2 months old (60-89 days) selected in Beijing, were assigned to four groups, 1 dose IPV plus 2 doses OPV (I-O-O), 2 doses IPV plus 1 dose OPV(I-I-O), 3 doses IPV (I-I-I), and 3 doses OPV (O-O-O), and were vaccinated at the age of 2, 3, 4 months, from 2009 to 2011. The frequencies of systemic as well as local injection site reactions after every dose were recorded and calculated. A total of 553 infants were enrolled in the study and 89 infants were quit, 1492 diseases were observed. RESULTS: The incidence of adverse events in I-O-O, I-I-O, I-I-I, O-O-O were 22.9% (94/410), 18.4% (60/327), 22.0% (78/354) and 17.7% (71/401) with no statistical differences (χ(2) = 4.84, P = 0.184). Dose 1 (22.7% (32/141)-35.3% (54/153) ) was more frequently than dose 2 and dose 3. No serious adverse events (SAE) were reported during the study. The incidence of systemic adverse reactions in I-O-O, I-I-O, I-I-I, O-O-O were 21.5% (88/410), 17.7% (58/327) , 20.1% (71/354) and 17.7% (71/401) with no statistical differences (χ(2) = 2.53, P = 0.472). Abnormal crying were the most frequency reactions (7.2% (29/401)-11.3% (37/327) ) in 4 groups. Rarely severe reactions were observed of abnormal crying, somnolence, irritability and mild or medium reactions occurred in other symptoms. Local adverse reactions such as injection site pain, scleroma and swelling were reported by 2.2% (5/229)-5.6% (22/393) ,0-0.9% (2/229) and 0-1.0% (4/393) in I-O-O,I-I-O and I-I-I, and most reactions were mild. CONCLUSION: Three IPV immunization and IPV/OPV sequential immunization as well as three OPV immunization demonstrated safe.

[Study of immunogenicity after primary vaccination by different sequential program of inactivated poliovirus vaccine and oral poliovirus vaccine].

OBJECTIVE: To evaluate immunogenicity after primary vaccination by different sequential program of inactivated poliovirus vaccine (IPV) and oral poliovirus vaccine (OPV). METHODS: Children of 2 months old (60-89 days) selected in Beijing were assigned to 4 groups, 1 dose IPV plus 2 doses OPV (I-O-O, 122 children), 2 doses IPV plus 1 dose OPV(I-I-O, 103 children), 3 doses IPV (I-I-I, 114 children), and 3 doses OPV (O-O-O, 106 children), and were vaccinated at the age of 2, 3, 4 months. Polio neutralizing antibody titers against poliovirus types 1, 2, and 3 were tested and protective rates were calculated before the 1st dose, after the last dose, and after the 1st and 2nd dose of IPV. RESULTS: After the primary immunization, geometric mean titers (GMT) of polio neutralizing antibody titers against poliovirus types 1, 2, and 3 were 788.32, 738.42 and 631.17 in O-O-O group, 212.02, 262.30 and 537.52 in I-I-I group, 940.35, 929.72 and 940.35 in I-O-O group and 901.09, 1102.68 and 1110.12 in I-I-O group (F values were 47.71, 53.84, and 9.81 respectively, all P values<0.01). The protective rate of three types among each group was 98.1% (104/106)-100.0% and the difference was not statistically significant (P>0.05). After the 1(st) dose of IPV, the GMT were 18.88, 37.77, 24.64 and the protective rate was 82.6% (122/138)-96.4% (133/138); after the 2nd dose of IPV, GMT were 177.03, 168.25, 321.86 and the protective rate was 99.1% (108/109)-100.0% (109/109) in antibody types 1, 2 and 3, respectively. CONCLUSION: GMT of polio neutralizing antibody titers against poliovirus is higher after vaccination by sequential program of IPV and OPV than that by IPV or OPV 3-doses program. High level of protective rate after 2 doses of IPV in I-I-O group may lead to better protection from vaccine associated paralytic poliomyelitis (VAPP). Sequential program of IPV and OPV can be used to maintain high level of herd immunity and to prevent VAPP, and the I-I-O sequential program should be the first choice.

[Study on the prevalence of acute flaccid paralysis and hand foot mouth disease in Beijing 2006 - 2008].

OBJECTIVE: To study the prevalence of acute flaccid paralysis (AFP) and hand foot mouth disease (HFMD) in Beijing, from 2006 - 2008. METHODS: Data on AFP and HFMD was analyzed epidemiologically, during 2006 - 2008 in Beijing. All the specimens from AFP cases were isolated and identified by RD and L20B cell and all of non-polio enterovirus (NPEV) cases were assayed by HFMD real-time PCR kit. The relationship between AFP and HFMD was analyzed. RESULTS: During 2006 - 2008, the number of AFP case in Beijing increased from 108 to 177 while the NPEV isolation rate increased from 11.11% to 20.34% and the positive rate of enterovirus 71 (EV71) and/or coxsackie virus A16 (Cox A16) increased from 0.93% to 10.17%. CONCLUSION: The prevalence of HFMD caused by EV71 and/or Cox A16 might have contributed to the increase of AFP cases in Beijing.

[Herd immunity against new influenza A (H1N1) in pre-vaccinated residents aged over 5 years in Beijing].

OBJECTIVE: To explore the herd immunity against influenza A (H1N1) in pre-vaccinated residents aged over 5 years, and therefore to provide data for vaccination policies in high risk populations. METHODS: From October to December 2009, Beijing CDC conducted a serum survey of the novel influenza A (H1N1) in the local residents, stratified in 10 age groups between 5 years to over 60 years, without H1N1 vaccination history and disease history. Hemagglutination inhibition (HI) assays were performed at Beijing CDC. Statistical significance was determined with geometric mean titer (GMT). RESULTS: 3499 serum samples were tested for HI antibody. The average level of HI antibody was 1:8.03, and 11.06% (387/3499) were sero-positive (HI antibody level ≥ 1:40). In the group aged from 5 to 19 years, the level of HI antibody and the sero-positive rate were higher (HI antibody > 1:8.9, sero-positive rate > 12%). CONCLUSIONS: The antibody levels in different groups were affected by age specific morbidity, and the higher antibody level of the school-age group was correlated with higher disease intensity in this population. The data showed that the herd immunity in Beijing was under the optimal level, but influenza A (H1N1) would probably become prevalent in the short coming future.