Facilitating Factor

[Marybelle Bailey]

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Objectives: To investigate and synthesize reasons for low access, initiation and adherence to antiretroviral drugs by mothers and exposed babies for prevention of mother-to-child transmission (PMTCT) of HIV in sub-Saharan Africa.

Methods: A systematic literature review was conducted. Four databases were searched (Medline, Embase, Global Health and Web of Science) for studies conducted in sub-Saharan Africa from January 2000 to September 2012. Quantitative and qualitative studies were included that met pre-defined criteria. Antiretroviral (ARV) prophylaxis (maternal/infant) and combination antiretroviral therapy (ART) usage/registration at HIV care and treatment during pregnancy were included as outcomes.

Results: Of 574 references identified, 40 met the inclusion criteria. Four references were added after searching reference lists of included articles. Twenty studies were quantitative, 16 were qualitative and eight were mixed methods. Forty-one studies were conducted in Southern and East Africa, two in West Africa, none in Central Africa and one was multi-regional. The majority (n=25) were conducted before combination ART for PMTCT was emphasized in 2006. At the individual-level, poor knowledge of HIV/ART/vertical transmission, lower maternal educational level and psychological issues following HIV diagnosis were the key barriers identified. Stigma and fear of status disclosure to partners, family or community members (community-level factors) were the most frequently cited barriers overall and across time. The extent of partner/community support was another major factor impeding or facilitating the uptake of PMTCT ARVs, while cultural traditions including preferences for traditional healers and birth attendants were also common. Key health-systems issues included poor staff-client interactions, staff shortages, service accessibility and non-facility deliveries.

Conclusions: Long-standing health-systems issues (such as staffing and service accessibility) and community-level factors (particularly stigma, fear of disclosure and lack of partner support) have not changed over time and continue to plague PMTCT programmes more than 10 years after their introduction. The potential of PMTCT programmes to virtually eliminate vertical transmission of HIV will remain elusive unless these barriers are tackled. The prominence of community-level factors in this review points to the importance of community-driven approaches to improve uptake of PMTCT interventions, although packages of solutions addressing barriers at different levels will be important.

The Sez6 family consists of Sez6, Sez6L, and Sez6L2. Its members are expressed throughout the brain and have been shown to influence synapse numbers and dendritic morphology. They are also linked to various neurological and psychiatric disorders. All Sez6 family members contain 2-3 CUB domains and 5 complement control protein (CCP) domains, suggesting that they may be involved in complement regulation. We show that Sez6 family members inhibit C3b/iC3b opsonization by the classical and alternative pathways with varying degrees of efficacy. For the classical pathway, Sez6 is a strong inhibitor, Sez6L2 is a moderate inhibitor, and Sez6L is a weak inhibitor. For the alternative pathway, the complement inhibitory activity of Sez6, Sez6L, and Sez6L2 all equaled or exceeded the activity of the known complement regulator MCP. Using Sez6L2 as the representative family member, we show that it specifically accelerates the dissociation of C3 convertases. Sez6L2 also functions as a cofactor for Factor I to facilitate the cleavage of C3b; however, Sez6L2 has no cofactor activity toward C4b. In summary, the Sez6 family are novel complement regulators that inhibit C3 convertases and promote C3b degradation.

This paper examines collusion among firms whose discount factors are private information. Mutual uncertainty regarding intentions to restrict competition might undermine the possibility of tacit collusion. Firms that want to collude may, however, reveal their intentions by consciously acting in breach of antitrust laws. As antitrust activity makes explicit collusion costly in expected terms, it can potentially be (ab)used as signaling device. We show that the fight against cartels may indeed facilitate collusion.

The incentive to coordinate behavior in order to increase profits is a powerful one. Despite the now widespread legal prohibitions on explicit coordination, firms continue to form cartels to restrict output or set prices.

Perhaps the most surprising thing about cartels is how pervasive they are. Over a century after the United States first adopted laws making price-fixing a felony, and two decades after the U.S., the European Commission, and competition authorities around the world reached consensus that hard core cartels would not be tolerated, cartels continue to form.

These observations raise the question of why companies continue to act in violation of antitrust laws. In this paper, we provide a rationale for the persistence of cartel formation. We show that firms may fix their prices precisely because it is prohibited.

This finding naturally leads to the question of whether firms can do better by colluding explicitly. To address this issue, we consider a similar setting as Harrington and Zhao (2012) and extend it by giving firms the opportunity to communicate directly. Specifically, each firm has to indicate at the beginning of the game whether it wants to engage in a cartel. In case of consensus, the cartel is formed. In principle, the possibility of express communication will not be of much help in this context when talking is cheap. However, firms can make communication costly by consciously acting in breach of antitrust laws. Gathering to discuss selling prices, for example, makes communication costly in expected terms due to antitrust enforcement. Additionally, there may be costs associated with setting up and maintaining the agreement (e.g. bargaining and monitoring).

With a few exceptions, existing literature on collusion does not make a clear distinction between tacit and explicit collusion. From an enforcement perspective, this is potentially problematic as the former is typically considered legal, whereas the latter is not.[2] As explicit collusion is costly, it is difficult to see why firms would use express communication if the same market outcome could be obtained in a tacit manner. One rationale for explicit collusion is that direct communication helps in coordinating on (more profitable) collusive equilibria. For instance, absent a focal price it may be difficult to coordinate actions without express communication. Moreover, explicit collusion may be more profitable when there is uncertainty about demand.[3] Communication also potentially plays a significant role when firms hold private information about factors that affect the sustainability of collusion (e.g. past actions, actual prices, realized sales).[4] In particular, firms may exchange information to enhance market transparency, thereby reducing the risk of secret price cutting.[5] Our analysis offers an alternative explanation for explicit collusion. In our setting, firms communicate neither to coordinate on a particular (more profitable) equilibrium nor for monitoring purposes. Firms explicitly discuss their prices solely to credibly signal their willingness to collude.

There are a few other studies that also highlight potential adverse effects of antitrust activity. McCutcheon (1997), for instance, argues that the prohibition of price-fixing might facilitate collusion by preventing renegotiations in case of defection, thereby making punishment strategies of cartel participants credible and effective. Bos, Peeters, and Pot (2013) show that when buyers do not instantly respond to price changes, firms may wish to collude explicitly when the probability of getting caught is sufficiently high. In a recent experiment, Andersson and Wengstrm (2007) find that costly communication leads to higher prices and enhances the stability of cartels. Our analysis adds to these findings by showing that antitrust laws can be (ab)used as signaling device and as such can be considered a facilitating factor for collusion.

This paper proceeds as follows. In the next section, we present the basic structure and assumptions of the model. Section 3 explores possibilities for firms to collude tacitly and explicitly. Specifically, we derive conditions under which tacit collusion is not feasible and show that firms may still be capable of reaching collusive market outcomes through express communication. Section 4 concludes.

Let us now direct our attention to possibilities for firms to collude. We start by analyzing tacit collusion and derive conditions under which tacit collusion is not feasible. Then, given these conditions, we show that firms may still be willing and able to collude explicitly. In both cases, the solution concept is a Bayesian Nash equilibrium (BNE).

In this section, we add an extra feature to the model by allowing firms to communicate directly and form a cartel. Specifically, after the information phase, both firms have to indicate whether they have an intention to collude. This is modeled as a choice from the set A,R, where A signifies the willingness to cartelize and R signifies refusal to collude. For a cartel to form, both firms have to choose A. We assume that explicit collusion is costly and when both firms choose A, their expected profit is reduced by a lump sum amount X>0. The amount X has a broad interpretation. It may be thought of as an investment of private resources required to form and maintain the cartel agreement. As explicit collusion typically constitutes a violation of antitrust laws, it also captures the anticipated costs of antitrust enforcement (e.g. fines, prison terms, treble damages to private parties).[9] At the end of this section, we provide an example illustrating that X may indeed include both types of costs.

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