Guinea-Bissau

Tuberculosis

The effect of revaccination with BCG in early childhood on mortality: a randomized trial in Guinea-Bissau. 2010, Roth, BMJ

Routine infant vaccines currently used in low income countries were not tested in randomized trials for their impact on overall child survival before their introduction. It has been assumed that the impact of a vaccine on mortality is proportional to the vaccine’s efficacy and the contribution of the target disease to overall mortality. The past 15 years of research on vaccines in low income countries, however, have shown that this assumption is not a tenable basis for vaccination policy, since vaccines have important non-specific effects. For example, measles and BCG vaccines have reported significant reductions in all-cause mortality, while Diphtheria-tetanus-pertussis (DTP) and high-titre measles vaccine has been associated with increased mortality, especially in girls.
The study was conducted in Guinea-Bissau to determine whether BCG revaccination at 19 months of age reduces overall child mortality. The trial was stopped prematurely because of a cluster of deaths in the BCG arm of the study. The hazard ratio for BCG revaccinated children compared with controls was 2.69.
The authors believed that this was not related to the BCG vaccinations itself, but to the DTP vaccine, which effect is somehow negatively altered by BCG, and to iron and vitamin A supplements that the children received during the experiment.

Measles

Measles and atopy in Guinea-Bissau. 1996, Shaheen, Lancet

In children in Guinea-Bissau, who had been ill with measles, the allergy was 3 times less common than in vaccinated children who did not get it. They allergic to a home dust mite 5 times less often.
Explained this is because the measles virus stimulates cellular immunity, whereas humoral immunity is responsible for allergies.
Children who have been breastfed for more than a year and children in pig houses have also had an allergy less often, according to indirect data, infections protect against allergies only if infection occurs in the p anneme age. Most likely, the reaction of T cells to allergens ripens to 5-7 years of age, and before that time it is changing under the influence of environmental factors such as infections.

Unvaccinated

The Introduction of Diphtheria-Tetanus-Pertussis and Oral Polio Vaccine Among Young Infants in the Urban African Community: A Natural Experiment. 2017, Mogensen, EBioMedicine

Due to the fact that in Guinea-Bissau children were vaccinated once in three months, it turned out to be a natural experiment. Some children have already been vaccinated by the age of 3-5 months, and some haven’t.
The risk of death in children vaccinated against diphtheria/tetanus/pertussis (DTP) was 10 times higher than that of the unvaccinated children. Children who were also vaccinated against poliomyelitis (OPV) died only 5 times more often that the unvaccinated children.
After vaccination started, infant mortality at the age over 3 months increased by 2 times.
The author of the study concludes that the vaccine against diphtheria/tetanus/pertussis kills more children than it saves.
The authors can hardly be accused of being anti-vaccination. Peter Aaby, one of the authors of the study, created Bandim Health Project in Guinea-Bissau, one of the main goals of which is to vaccinate children.

Unvaccinated

DTP with or after measles vaccination is associated with increased in-hospital mortality in Guinea-Bissau. 2007, Aaby, Vaccine

Children from Guinea-Bissau, who received a diphtheria/tetanus/pertussis vaccine together with the measles vaccine died twice more often that those who only received a measles vaccine.
Authors cite several more studies with the same results in Gambia, Malawi, Congo, Ghana and Senegal.

Unvaccinated

Co-administration of live measles and yellow fever vaccines and inactivated pentavalent vaccines is associated with increased mortality compared with measles and yellow fever vaccines only. An observational study from Guinea-Bissau. 2014, Fisker, Vaccine

Children who received a pentavalent vaccine (diphtheria/tetanus/pertussis/Hib/hepatitis B), in addition to measles and yellow fever vaccines, died 7.7 times more often than the children who did not receive a pentavalent vaccine.
In this lecture Susan Humphries explains why the combination of live and killed vaccines leads to this effect.

SIDS

Evidence of Increase in Mortality After the Introduction of Diphtheria-Tetanus-Pertussis Vaccine to Children Aged 6-35 Months in Guinea-Bissau: A Time for Reflection? 2018, Aaby, Front Public Health

Метаанализ трех исследований в Гвинее-Биссау. Среди привитых DTP смертность была в 2 раза выше, чем среди непривитых, особенно среди девочек. Вдобавок, непривитые дети были обычно слишком больные или слишком слабые для прививки, и хуже питались. Они чаще находились в сельской местности, где смертность выше. Поэтому, пишут авторы, негативный эффект вакцинации в этих исследованиях занижен.
Не существует ни одного проспективного исследования, свидетельствующего, что вакцинация DTP ассоциирована с пониженной смертностью. Более того, на протяжении последних 20 лет несколько исследований выявили, что DTP ассоциирована с повышенной смертностью, особенно среди девочек. Тем не менее, охват тремя дозами именно этой вакцины используется в качестве главного индикатора успеха программ вакцинации. Учитывая, что все исследования, включая это, свидетельствуют, что DTP повышает смертность среди девочек - это очень нелогичная позиция. Нам следует использовать показатели эффективности программы, которые положительно связаны с улучшением выживаемости детей.
Эксперты ВОЗ утверждают, что негативный эффект DTP преувеличен, потому что исследования проводились в местности, где действовал коллективный иммунитет от коклюша, и поэтому преимущества прививки не были видны. Однако коклюш был эндемичным до начала программы вакцинации в Гвинее-Биссау, тем не менее, все три исследования показали повышенную смертность ассоциированную с DTP.

Лицензия Creative Commons Content above is licenced under Creative Common Attribution—NonCommercial—NoDerivatives (CC BY-NC-ND) licence,
i.e. it is free for non-commercial distribution and citation with this reference being provided: scibook.org, amantonio, using the content to create another product or meaning is prohibited.
scibook.org, 2017-2019