Sabin-IPV produces VAPP protection comparable with Salk-IPV
A Sabin strain-based inactivated poliovirus vaccine administered to Chinese infants rendered an immune response against vaccine-associated paralytic poliomyelitis that was comparable to Salk inactivated poliovirus vaccine, according to recently published study findings.
“A Sabin strain-based inactivated poliovirus vaccine (Sabin-IPV, Pfizer) is recommended for use in developing countries and regions based upon considerations such as replacing OPV by IPV to decrease and eliminate [vaccine-associated paralytic poliomyelitis (VAPP)],” Guoyang Liao, PhD, from the Institute of Medical Biology at Chinese Academy of Medical Science and Peking Union Medical College, and colleagues wrote. “However, the greatest concern related to switching from a live to an inactivated vaccine is whether effective immunogenicity can be ensured with the inactivation process.”
Liao and colleagues conducted a double masked, parallel-group noninferiority trial that included 1,200 infants aged 60 to 90 days to evaluate the immune efficacy and safety of Sabin-IPV compared with Salk-IPV (Sanofi Pasteur). The researchers randomly assigned the patients into experimental (Sabin-IPV) and control (Salk-IPV) groups, and each infant received three IV doses at 30-day intervals and a booster at age 18 months.
There were 600, 591 and 581 infants, respectively, who received the first, second and third doses of Sabin-IPV; while the controls who received Salk-IPV numbered 600, 584 and 573 for each consecutive dose. More than 90% of infants in the experimental group developed antibodies for poliovirus type I (100%), type II (94.9%) and type III (99%) at 1 month after their third dose. Similar results occurred in the control group.
Both groups underwent a significant decline in neutralizing antibodies against all polio types before receiving a booster shot. Subsequently, both Sabin-IPV and Salk-IPV infants experienced significant immune response against all three poliovirus types.
In addition, “645 and 688 episodes of unsolicited adverse events were reported among 323 and 326 infants in both the Sabin-IPV and Salk-IPV groups, and almost all were attributed to respiratory tract infections (43.3% in the Sabin-IPV group; 43.8% in the Salk-IPV group),” the researchers wrote.
“These findings, especially its immunogenicity as similar with that of Salk-IPV, suggest that Sabin-IPV is a viable alternative to OPV, especially for use in the [expanded program on immunization] in developing countries,” the researchers wrote. “The use of Sabin-IPV could potentially prevent the occurrence of VAPP in these areas and will be helpful for new children immunization programs of the single dose of IPV preceding the bivalent OPV, which is recommended by WHO and actually is processed for trivalent OPV replacement in the most developing areas recently.” – by Kate Sherrer
Disclosure: The researchers report no relevant financial disclosures.