Polack et al. (Dec. 31)¹ report a vaccine efficacy of 94.8% against Covid-19 after two doses of the messenger RNA (mRNA) vaccine BNT162b2 (Pfizer–BioNTech). The authors also report a vaccine efficacy of 52.4% from after the first dose to before the second dose, but in their calculation, they included data that were collected during the first 2 weeks after the first dose, when immunity would have still been mounting.¹ We used documents submitted to the Food and Drug Administration² to derive the vaccine efficacy beginning from 2 weeks after the first dose to before the second dose ( Table 1 ). Even before the second dose, BNT162b2 was highly efficacious, with a vaccine efficacy of 92.6%, a finding similar to the first-dose efficacy of 92.1% reported for the mRNA-1273 vaccine (Moderna).³

Since its introduction by the Nuremberg Code and the Declaration of Helsinki, the place held by ethics in biomedical research has been continuously increasing in importance. The past 30 years have also seen exponential growth in the number of biomedical articles published. A systematic review of the literature is the scientific way of synthesising a plethora of information, by exhaustively searching out and objectively analysing the studies dealing with a given issue. However, the question of ethics in systematic reviews is rarely touched upon. This could lead to some drawbacks, as systematic reviews may contain studies with ethical insufficiencies, may be a possible way to publish unethical research and may also be prone to conflict of interest. Finally, informed consent given for an original study is not necessarily still valid at the systematic review level. There is no doubt that routine ethical assessment in systematic reviews would help to improve the ethical and methodological quality of studies in general. However, ethical issues change so much with time and location, and are so broad in scope and in context that it appears illusory to search for a universal, internationally accepted standard for ethical assessment in systematic reviews. Some simple suggestions could nevertheless be drawn from the present reflection and are discussed in the paper.

Little is known on the prevalence of tooth decay among pregnant women. Better knowledge of tooth decay risk indicators during pregnancy could help to develop follow-up protocols for women at risk, along with better prevention strategies. The aim of this study was to assess the frequency of tooth decay and the number of decayed teeth per woman in a large sample of pregnant women in France, and to study associated risk indicators. A secondary cross-sectional analysis of data from a French multicentre case-control study was performed. The sample was composed of 1094 at-term women of six maternity units. A dental examination was carried out within 2 to 4 days post-partum. Socio-demographic and behavioural characteristics were obtained through a standardised interview with the women. Medical characteristics were obtained from the women’s medical records. Risk indicators associated with tooth decay were identified using a negative binomial hurdle model. 51.6% of the women had tooth decay. The mean number of decayed teeth among women having at least one was 3.1 (s.d. = 2.8). Having tooth decay was statistically associated with lower age (aOR = 1.58, 95%CI [1.03,2.45]), lower educational level (aOR = 1.53, 95%CI [1.06,2.23]) and dental plaque (aOR = 1.75, 95%CI [1.27,2.41]). The number of decayed teeth was associated with the same risk indicators and with non-French nationality and inadequate prenatal care. The frequency of tooth decay and the number of decayed teeth among pregnant women were high. Oral health promotion programmes must continue to inform women and care providers about the importance of dental care before, during and after pregnancy. Future research should also assess the effectiveness of public policies related to oral health in target populations of pregnant women facing challenging social or economic situations.