The efficacy of vaccines is a complex issue and sometimes long range effects may be disastrous.
The situation is dramatic for the RTS,S vaccine which protects only against sporozoites but does not induce clinical immunity against blood-stage parasites. The vaccine showed evidence of 35,9% efficacy in the first year after vaccination, but efficacy fell to 2.5% in the fourth year. The cohort with a high exposure index even showed a negative efficacy during the fifth year, i.e. an higher level of infection
Olotu A, Fegan G, Wambua J, et al. Seven-Year Efficacy of RTS,S/AS01 Malaria Vaccine among Young African Children. N Engl J Med. 2016;374(26):2519-2529. doi:10.1056/NEJMoa1515257
Disturbing facts were also evidenced for the corona vaccines. A recent study which used COVID-19 data provided by the Our World in Data for cross-country analysis, available as of September 3, 2021 on a worldwide basis, found that the trend line suggests a marginally positive association such that countries with higher percentage of population fully vaccinated have higher COVID-19 cases per 1 million people.
It is also emerging that immunity derived from the Pfizer-BioNTech vaccine may not be as strong as immunity acquired through recovery from the COVID-19 virus. The sole reliance on vaccination as a primary strategy to mitigate COVID-19 and its adverse consequences needs to be re-examined. In a report released from the Ministry of Health in Israel, the effectiveness of 2 doses of the Pfizer vaccine was reported to be 39 % only.
Subramanian SV, Kumar A. Increases in COVID-19 are unrelated to levels of vaccination across 68 countries and 2947 counties in the United States [published online ahead of print, 2021 Sep 30]. Eur J Epidemiol. 2021;1-4. doi:10.1007/s10654-021-00808-7
In summary, as efforts are made to encourage populations to get vaccinated it should be done so with humility and respect. Stigmatizing populations can do more harm than good.